navsea-sw030-aa-mmo-010-2009

NAVSEA SW030-AA-MMO-010 SIXTH REVISION

0640-LP-108-4876

This Manual Supersedes NAVSEA SW030-AA-MMO-010, Dated 09 November 2004

DISTRIBUTION STATEMENT D: Distribution authorized to DoD and DoD Contractors; criticaltechnology; 25 March 2009, other requests must be referred to the NAVSEA, PM Navy 2TConventional Ammunition Systems (NCAS), Buffington Road, B171 Annex, Picatinny Arsenal, NJ07806-5000.

WARNING: This document contains technical data whose export is restricted by the Arms ExportControl Act (Title 22, O.S.C. Sec. 2751 ET. Seq.) or Executive Order 12470. Violations of these exportlaws are subject to severe criminal penalties.

DESTRUCTION NOTICE: Destroy by any method that will prevent disclosure of contents orreconstruction of the document.

Published by Direction of Commander, Naval Sea Systems Command

TECHNICAL MANUAL

NAVY GUN AMMUNITIONDESCRIPTION, OPERATION, AND MAINTENANCE

FOR OFFICIAL USE ONLY

25 March 20090640-LP-108-4876

*0640LP1084876*SW030-AA-MMO-010

SW030-AA-MMO-010

List of Effective PagesReproduction for nonmilitary use of the information or illustrations contained in this manual is not per-

mitted. The policy for Navy and Marine Corps use reproduction is established in OPNAVINST 5510.1 SERIES.

Original....................................................25 March 2009

Total number of pages in this manual is 322 consisting of the following:

Title ............................................................................... 0A . .................................................................................. 0Cert-1............................................................................. 0Cert-2 blank................................................................... 0Change Record .............................................................. 0Change Record-2 blank................................................. 0Foreword-1 .................................................................... 0Foreword-2 blank .......................................................... 0i – xi............................................................................... 0xii blank......................................................................... 01-1 – 1-7 ........................................................................ 01-8 blank........................................................................ 02-1 – 2-14 ...................................................................... 03-1 – 3-34 ...................................................................... 04-1 – 4-113 .................................................................... 04-114 blank.................................................................... 0

5-1 – 5-14.......................................................................06-1 – 6-6.........................................................................0A-1 – A-57 .....................................................................0 A-58 blank .....................................................................0B-1 – B-7 .......................................................................0B-8 blank........................................................................0C-1 – C-27 .....................................................................0C-28 blank......................................................................0D-1 - D-4........................................................................0E-1 - E-2.........................................................................0F-1 - F-3 .........................................................................0F-4 blank ........................................................................0TMDER 1 - TMDER 6 ..................................................0Back Cover blank...........................................................0Back Cover ....................................................................0

*Zero in this column indicates an original page

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SW030-AA-MMO-010

FOREWORD

This technical manual provides information on Navy surface gun ammunition over .60 caliber and items closely associated with gun ammunition. It has been prepared for use by all Navy personnel engaged in the preparation, handling, and tactical use of Navy gun ammunition.

Ammunition and components are not to be restricted or declared unserviceable based solely on the information contained in this manual.

Ships, training activities, supply points, depots, Naval Shipyards and Supervisors of Shipbuilding are requested to arrange for the maximum practical use and evaluation of NAVSEA technical manuals (TMS). All errors, omissions, discrepancies, and suggestions for improvement to NAVSEA TMs shall be for-warded to: Commander, Code 310, TMDERs, NAVSURFWARCENDIV NSDSA, 4363 Missile Way, Bldg 1388, Port Hueneme, California 93043-4307 on NAVSEA Technical Manual Deficiency/Evaluation Report, NAVSEA Form 4160/1. All feedback comments shall be thoroughly investigated and originators will be advised of action resulting therefrom. Three copies of form NAVSEA 4160/1 are included at the end of each separately bound technical manual 8-½ x 11 inches or larger. Copies of form NAVSEA 4160/1 may be requisitioned from the Naval Systems Data Support Activity, Code 310 at the above address. Users are encouraged to transmit deficiency submittals via the Naval Systems Data Support Activity Web page located at: https://nsdsa2.phdnswc.navy.mil

The contents of this manual are official and reflect the engineering and maintenance data available. Cutoff date for information contained herein is 31 August 2008.

Distance support/anchor desk is available via the web at http://www.anchordesk.navy.mil and via toll free number 1-877-4-1-TOUCH (86824).

Activities within the Department of Defense having need of this manual may contact Commander, NSWC Crane, Joint Special Operations Response Department, Munitions Division (Technical Manuals Group), Bldg 3373, 300 Hwy. 361, Crane, IN 47522-5001 for copies.

Foreword-1/(Foreword-2 blank)

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Chapter/Paragraph Page

List of Figures ............................................................................................................................................. iiiList of Tables................................................................................................................................................ ixSafety Summary ........................................................................................................................................... xi

1 INTRODUCTION1-1. Safety Summary .................................................................................................................................... 1-11-2. Reporting of Explosive Mishaps ........................................................................................................... 1-11-3. Scope ..................................................................................................................................................... 1-11-4. Intended Use .......................................................................................................................................... 1-21-5. Arrangement of Content ........................................................................................................................ 1-21-6. Reference Data ...................................................................................................................................... 1-2

2 AMMUNITION INFORMATION2-1. Scope ..................................................................................................................................................... 2-12-2. Identification.......................................................................................................................................... 2-12-3. Classification of Gun Ammunition........................................................................................................ 2-22-4. Gun Ammunition Components and Shipping Containers ..................................................................... 2-32-5. Selection of Projectiles and Fuzes for Different Targets..................................................................... 2-10

3 AMMUNITION ASSEMBLIES3-1. Introduction ........................................................................................................................................... 3-13-2. 20 Millimeter Ammunition.................................................................................................................... 3-13-3. 25 Millimeter Ammunition.................................................................................................................... 3-83-4. 30 Millimeter Ammunition.................................................................................................................. 3-113-5. 40 Millimeter Ammunition.................................................................................................................. 3-153-6. 57 Millimeter Ammunition.................................................................................................................. 3-173-7. 76 Millimeter Ammunition.................................................................................................................. 3-203-8. 5-Inch, 54 Caliber Ammunition........................................................................................................... 3-24

4 FUZES4-1. General................................................................................................................................................... 4-14-2. Point Detonating (PD) Fuzes................................................................................................................. 4-44-3. Mechanical Time (MT and MT/PD) Fuzes ......................................................................................... 4-174-4. Electronic Time (ET) Fuzes ................................................................................................................ 4-244-5. Proximity Fuzes................................................................................................................................... 4-254-6. Multiple Function Fuzes...................................................................................................................... 4-944-7. Auxiliary Detonating Fuzes............................................................................................................... 4-108

5 PRIMERS5-1. Introduction ........................................................................................................................................... 5-15-2. Classification of Primers ....................................................................................................................... 5-15-3. Electric Primers ..................................................................................................................................... 5-25-4. Percussion Primers ................................................................................................................................ 5-75-5. Combination Primers........................................................................................................................... 5-105-6. Firing Circuit Test ............................................................................................................................... 5-12

6 EXPLOSIVES6-1. Introduction ........................................................................................................................................... 6-1

TABLE OF CONTENTS

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TABLE OF CONTENTS (Continued)

6-2. Propellant ............................................................................................................................................... 6-16-3. High Explosives ..................................................................................................................................... 6-4

Appendix A Historical Data.................................................................................................................... A-1A-1. General .................................................................................................................................................. A-1A-2. Separate Loaded Ammunition .............................................................................................................. A-4A-3. Ammunition .......................................................................................................................................... A-6A-4. Fuze..................................................................................................................................................... A-40A-5. Primers ................................................................................................................................................ A-41A-6. Tracers................................................................................................................................................. A-48A-7. Black Powder ...................................................................................................................................... A-56

Appendix B Nose Fuze Removal/Replacement, and Setting ................................................................. B-1B-1. Fuze Setters and Wrenches ................................................................................................................... B-1

Appendix C Ammunition and Fuze Data Sheets .................................................................................... C-1Index of Figures ........................................................................................................................................ C-1Appendix D Mark Index ......................................................................................................................... D-1Appendix E DODIC/Nomenclature Current Index .................................................................................E-1Appendix F DODIC/Nomenclature Historical Index..............................................................................F-1

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Figure 2-1 Types of Gun Ammunition: Fixed and Separated ............................................................................ 2-3Figure 2-2 Typical Projectile, External View ..................................................................................................... 2-4Figure 2-3 Components of Propelling Charge in Case (Fixed) Ammunition ..................................................... 2-6Figure 2-4 Components of Propelling Charge in Separated Ammunition .......................................................... 2-6Figure 2-5 Miscellaneous Gun Ammunition Components and Details .............................................................. 2-8Figure 2-6 Typical Polyurethane Plug................................................................................................................. 2-9Figure 2-7 Typical Waterproof Protective Cap ................................................................................................... 2-9Figure 2-8 Typical Box-Type Containers ......................................................................................................... 2-11Figure 2-9 Typical Tank-Type Container ......................................................................................................... 2-12Figure 3-1 20 Millimeter Armor-Piercing, Discarding Sabot Projectile, MK 68 ............................................... 3-2Figure 3-2 20 Millimeter MK 7 Loading Links .................................................................................................. 3-2Figure 3-3 20 Millimeter Enhanced Lethality Cartridge, Armor-Piercing, Discarding Sabot Projectile............ 3-2Figure 3-4 M8 and M10 Disintegrating Links for 20 Millimeter M90 and M200 Series ................................... 3-4Figure 3-5 20 Millimeter Armor-Piercing, Tracer (M95) Projectile................................................................... 3-5Figure 3-6 20 Millimeter Incendiary (M96) Projectile ....................................................................................... 3-5Figure 3-7 20 Millimeter Propelling Charge ....................................................................................................... 3-6Figure 3-8 20 Millimeter High Explosive Incendiary (M210) Projectile ........................................................... 3-7Figure 3-9 25 Millimeter Armor-Piercing, Discarding Sabot Tracer Projectile (M791) .................................... 3-8Figure 3-10 25 Millimeter Target Practice, Tracer Projectile (M793).................................................................. 3-9Figure 3-11 25 Millimeter High Explosive Incendiary Projectile MK 210 .......................................................... 3-9Figure 3-12 25 Millimeter Semi-Armor-Piercing High Explosive Incendiary Projectile (PGU-32/U)................ 3-9Figure 3-13 30 Millimeter Armor-Piercing, Fin-Stabilized, Discarding Sabot, Traced (APFSDS-T)

(MK 258)........................................................................................................................................ 3-12Figure 3-14 30 Millimeter Armor-Piercing, Fin-Stabilized, Discarding Sabot, Traced (APFSDS-T)

(MK 268)......................................................................................................................................... 3-12Figure 3-15 30 Millimeter High Explosive, Incendiary, Traced (HEI-T) (MK 266)......................................... 3-13Figure 3-16 30 Millimeter Multi-Purpose, Low Drag, Traced (MPLD-T) (MK 264) ....................................... 3-13Figure 3-17 30 Millimeter Target Practice, Traced (TP-T) (MK239)................................................................. 3-14Figure 3-18 40 Millimeter Propelling Charge Assembly .................................................................................... 3-15Figure 3-19 40 Millimeter Blank Saluting Charge, DODIC B650 (200 g.)........................................................ 3-15Figure 3-20 40 Millimeter Blank Saluting Charge, DODIC B550 (50 g.).......................................................... 3-16Figure 3-21 MK 806 Container ........................................................................................................................... 3-19Figure 3-22 M8 Clip............................................................................................................................................ 3-19Figure 3-23 76 Millimeter High Explosive Projectile (Point Detonating or Proximity)..................................... 3-22Figure 3-24 76 Millimeter Target Practice, Variable Time-Nonfragmenting Projectile..................................... 3-22Figure 3-25 76 Millimeter Blind Loaded and Plugged Projectile ....................................................................... 3-22Figure 3-27 76 Millimeter Clearing Charge........................................................................................................ 3-23Figure 3-26 76 Millimeter Propelling Charge ..................................................................................................... 3-23Figure 3-28 5-Inch, 54-Caliber High Explosive Projectile ................................................................................. 3-25Figure 3-29 5-Inch, 54-Caliber High-Fragmentation Projectile.......................................................................... 3-31Figure 3-30 5-Inch, 54-Caliber High Capacity Projectile ................................................................................... 3-31Figure 3-31 5-Inch, 54-Caliber Illuminating Projectile....................................................................................... 3-31Figure 3-32 5-Inch, 54-Caliber White Phosphorus Projectile ............................................................................. 3-32

LIST OF FIGURES

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LIST OF FIGURES (Continued)

Figure 3-33 5-Inch, 54-Caliber Target Practice (Puff) Projectile ........................................................................ 3-32Figure 3-34 5-Inch, 54-Caliber Nonfragmenting Projectile ................................................................................ 3-33Figure 3-35 5-Inch, 54-Caliber Propelling Charge.............................................................................................. 3-33Figure 4-1 Forces That Work on Fuzes ............................................................................................................... 4-2Figure 4-2 Fuze MK 27 MOD 1 (Point Detonating), Unarmed and Armed Positions, Cutaway Views ............ 4-5Figure 4-3 Fuze MK 30 MOD 3 (Point Detonating), Unarmed, Cross-Sectional View with Setting

Screw in OFF Position ....................................................................................................................... 4-6Figure 4-4 Fuze MK 30 MOD 5 (Point Detonating), Unarmed and Armed Cross-Sectional Views.................. 4-8Figure 4-5 Fuze MK 30 MODs 2-4, and MK 66 MOD 0 (Point Detonating), Incorrect and Correct

Fuze Settings ...................................................................................................................................... 4-8Figure 4-6 Fuze MK 30 MODs 2 3 and 4 (Left) and MOD 5 (Right) (Point Detonating), External View......... 4-9Figure 4-7 Fuze MK 399 MOD 0 (Point Detonating), Cross-Sectional and External Views ........................... 4-10Figure 4-8 Fuze MK 407 MOD 0 (Point Detonating - Superquick/Delay), Cutaway and External Views ...... 4-14Figure 4-9 Fuze MK 407 MOD 1 (Point Detonating/Delay), Cross-Sectional View........................................ 4-15Figure 4-10 Fuze M505A3 (Point Detonating), Cutaway and External Views................................................... 4-16Figure 4-11 Typical Mechanical Time Fuze, Cutaway View.............................................................................. 4-18Figure 4-12 Typical Mechanical Time Fuze Timing Mechanism (Early Version), Schematic View................. 4-19Figure 4-13 Fuze MK 342 MOD 0 (Mechanical Time), External View ............................................................. 4-22Figure 4-14 Fuze MK 393 MOD 0 (Mechanical Time/Point Detonating), Cross-Sectional View ..................... 4-23Figure 4-15 Rear Fitting Safety Device ............................................................................................................... 4-29Figure 4-16 Reed Spin Switch, External and Cross Sectional Views ................................................................. 4-31Figure 4-17 Operational Sequence of Variable Time-Radio Frequency Fuze Components when Fired from

a Gun ................................................................................................................................................ 4-32Figure 4-18 Solid-State VT-RF Fuze Block Diagram ......................................................................................... 4-35Figure 4-19 Typical Projectile Electrical Field Radiation Pattern, Cross Section............................................... 4-36Figure 4-20 Air Target and VT-RF Fuzed-Projectile Engagement, Vector Diagram ......................................... 4-38Figure 4-21 Wave Noise Amplitude Distribution and A-Sen Response Curves for VT-RF Fuzes .................... 4-39Figure 4-22 MK 70-Series Fuze Tube-Type Firing Circuit Schematic ............................................................... 4-40Figure 4-23 MK 70-Series, MK 417, MK 418 Fuze Solid-State Firing Circuit Schematic ................................ 4-42Figure 4-24 Fuze MK 73 (Variable Time-Radio Frequency), Cutaway View.................................................... 4-43Figure 4-25 Fuze MK 417 MOD 0 (Variable Time-Radio Frequency), Cutaway View..................................... 4-45Figure 4-26 Fuze MK 418 MOD 0 (Variable Time-Radio Frequency), Cutaway View..................................... 4-46Figure 4-27 Arming Sequence of M513A2, M514A1, and M728 CVT Fuzes ................................................... 4-48Figure 4-28 Arming Sequence of M732 CVT Fuze in MK 143 Projectiles........................................................ 4-49Figure 4-29 CVT Fuze M728, Quarter Section View ......................................................................................... 4-51Figure 4-30 Operational Sequence of Projectiles Fuzed with Controlled Variable Time Fuzes M514 and

M728 ................................................................................................................................................ 4-54Figure 4-31 Controlled Variable Time Fuze M732/Fuze Setter M27 Interface .................................................. 4-58Figure 4-32 CVT Fuze M732, Quarter Section View ......................................................................................... 4-59Figure 4-33 Surface Target Engagement, Velocity Vector Diagram .................................................................. 4-63Figure 4-34 O-Sen Response Curves................................................................................................................... 4-64Figure 4-35 Fuze M728, Block Diagram............................................................................................................. 4-65Figure 4-36 Fuze M732, Block Diagram............................................................................................................. 4-66

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Figure 4-37 M728 and M732 Fuze Radiation Pattern, Cross Section................................................................. 4-66Figure 4-38 Fuze M728 Firing and CVT Switching Circuit Schematic ............................................................. 4-70Figure 4-39 Fuze MK 732 Firing and CVT Switching Circuit Schematic ......................................................... 4-71Figure 4-40 Projected View of CVT Fuze M513A2/M514A1 Time Setting Scale (Shown Set at 20 Sec.) ...... 4-72Figure 4-41 Projected View of CVT Fuze M728 Time Setting Scale (Shown Set at 20 Sec.)........................... 4-72Figure 4-42 Projected View of CVT Fuze M732 Time Setting Scale (Shown Set at 20 Sec.)........................... 4-72Figure 4-43 Optical Components of VT-IR Fuze, Exploded View .................................................................... 4-78Figure 4-44 Optics Assembly Package For All Other IR Fuzes ......................................................................... 4-79Figure 4-45 Solar and Target Radiation vs. Wavelength .................................................................................... 4-82Figure 4-46 Optical Components, Detector Pattern, and Look Angles for all VT-IR Fuzes .............................. 4-83Figure 4-47 Window Filter and Detector Response Curves for VT-IR Fuzes .................................................... 4-84Figure 4-48 Calculated Detector Output Signals for VT-IR Fuzes..................................................................... 4-85Figure 4-49 Detector Signal Envelopes at Selected Radial Miss Distances ....................................................... 4-86Figure 4-50 MK 90-Series Fuze-Block Diagram ................................................................................................ 4-87Figure 4-51 MK 90 Series Firing Circuit Schematic .......................................................................................... 4-88Figure 4-52 Fuze MK 404, Block Diagram ........................................................................................................ 4-89Figure 4-53 Fuze MK 404, Firing Circuit Diagram ............................................................................................ 4-90Figure 4-54 Fuze MK 91 (Variable Time-Infrared), Cutaway View .................................................................. 4-92Figure 4-55 Fuze MK 404 MODs 0 and 1 (Variable Time-Infrared), Cutaway View ....................................... 4-93Figure 4-56 Multi-Function Radio Frequency Fuze............................................................................................ 4-94Figure 4-57 S&A Locking Features .................................................................................................................... 4-98Figure 4-58 Electrical Safety Pertaining to Firing Circuit Operation ............................................................... 4-101Figure 4-59 AIR Mode Geometry ..................................................................................................................... 4-103Figure 4-60 3P Fuze Components ..................................................................................................................... 4-106Figure 4-61 Fuzes MK 54 MOD 2, MK 55 MOD 0 and MK 89 MOD 0 (Auxiliary Detonating), Cutaway

View and Exploded View of Arming Mechanism ........................................................................ 4-108Figure 4-62 Delay Arming Safety Device MK 41 MODs 0 and 1, Assembled View and View with Top

Plate Removed............................................................................................................................... 4-111Figure 4-63 Typical Applications of Fuze MK 395 MOD 0 (Auxiliary Detonating), Cross-Sectional View.. 4-112Figure 4-64 Fuze MK 396 MOD 0 (Auxiliary Detonating), Cross Sectional View ......................................... 4-113Figure 4-65 Fuze MK 411 (Auxiliary Detonating), Cross-Sectional View ...................................................... 4-113Figure 5-1 Typical Case Electric Primer, Cutaway View ................................................................................... 5-3Figure 5-2 Primer MK 45 MOD 1 (Electric), Cross-Sectional View.................................................................. 5-4Figure 5-3 Primer MK 48 MOD 2 (Electric), Cross-Sectional View.................................................................. 5-5Figure 5-4 Primer M52A3B1 (Case Electric), Cross-Sectional View ................................................................ 5-6Figure 5-5 Primer MK 153 MOD 1 (Case Electric), Cross-Sectional View....................................................... 5-6Figure 5-6 Percussion Cap Type Primer, Cutaway View ................................................................................... 5-7Figure 5-7 Typical Case Percussion Primer, Cutaway View .............................................................................. 5-8Figure 5-8 Primer MK 22 MODs 1 and 2 (Case Percussion), Cross-Sectional View......................................... 5-9Figure 5-9 Primer MK 161 MOD 0 (Percussion), Cross-Sectional View......................................................... 5-10Figure 5-10 Primer MK 15 MOD 2 (Lock Combination), Cross-Sectional View.............................................. 5-11Figure 5-11 MK 55 MOD 0 Electronic Firing Circuit Tester ............................................................................. 5-14Figure 6-1 Propellant Grain Web Locations ....................................................................................................... 6-4

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Figure 6-2 Pressure-Travel Curve........................................................................................................................ 6-4Figure A-1 Mandatory Gas Check Seal Requirements for Acceptable Product ................................................. A-2Figure A-2 Slight Gap Around Gas Check Seal - Acceptable Condition............................................................ A-2Figure A-3 Multiple Press of Gas Check Seal - Acceptable Condition .............................................................. A-2Figure A-5 Entire Gas Check Seal Missing - Unacceptable Condition............................................................... A-3Figure A-4 Canted Gas Check Seal - Acceptable Condition............................................................................... A-3Figure A-6 Inverted Gas Check Seal - Unacceptable Condition ......................................................................... A-3Figure A-7 Missing Lead Core - Unacceptable Condition.................................................................................. A-3Figure A-8 Gas Check Seal Not Fully or Properly Seated - Unacceptable Condition ........................................ A-4Figure A-9 Gas Check Seal Seated Above Either or Both Projectile Base and Fuze/Plug Unacceptable

Condition........................................................................................................................................... A-4Figure A-10 Torn, Cut or Gouged Gas Check Seal - Unacceptable Condition..................................................... A-4Figure A-11 Separate Loaded Bag Charge............................................................................................................ A-5Figure A-12 Bag Charges: Stacked and Dumped................................................................................................. A-6Figure A-13 40 Millimeter High Explosive, Plugged Projectile ........................................................................... A-8Figure A-14 40 Millimeter High Explosive, Incendiary, Plugged Projectile ........................................................ A-8Figure A-15 40 Millimeter High Explosive, Incendiary, Self-Destruct Projectile................................................ A-9Figure A-16 40 Millimeter High Explosive, Incendiary, Tracer, Non-Self-Destruct Projectile ........................... A-9Figure A-17 40 Millimeter High Explosive, Incendiary Tracer, Self-Destruct Projectile .................................. A-10Figure A-18 40 Millimeter High Explosive Incendiary Tracer, Dark Ignition, Self-Destruct Projectile............ A-10Figure A-19 40 Millimeter High Explosive Tracer, Self-Destruct Projectile ..................................................... A-10Figure A-20 40 Millimeter Propelling Charge Assembly ................................................................................... A-11Figure A-21 5-Inch, 38-Caliber High Explosive Projectile................................................................................. A-18Figure A-22 5-Inch, 38-Caliber High Capacity Projectile................................................................................... A-20Figure A-23 5-Inch, 38-Caliber Antiaircraft Common Projectile ....................................................................... A-20Figure A-24 5-Inch, 38-Caliber Rocket Assisted Projectile ................................................................................ A-21Figure A-25 5-Inch, 38-Caliber Common Projectile ........................................................................................... A-21Figure A-26 5-Inch, 38-Caliber Illuminating Projectile ...................................................................................... A-21Figure A-27 5-Inch, 38-Caliber White Phosphorus Projectile ............................................................................ A-22Figure A-28 5-Inch, 38-Caliber Nonfragmenting Target Practice Projectile ...................................................... A-22Figure A-29 5-Inch, 38-Caliber Target Practice (Puff) Projectile ....................................................................... A-23Figure A-30 5-Inch, 38-Caliber Chaff Dispensing Projectile.............................................................................. A-23Figure A-31 5-Inch, 38-Caliber Propelling Charge............................................................................................. A-24Figure A-32 5-Inch, 54 Caliber Antiaircraft Common Projectile........................................................................ A-26Figure A-33 5-Inch, 54-Caliber Rocket Assisted Projectile ................................................................................ A-27Figure A-34 5-Inch, 54-Caliber Common Projectile ........................................................................................... A-27Figure A-35 5-Inch, 54-Caliber Chaff Dispensing Projectile.............................................................................. A-27Figure A-36 6-Inch, 47-Caliber Antiaircraft Common Projectile ....................................................................... A-29Figure A-37 6-Inch, 47-Caliber High Capacity Projectile................................................................................... A-29Figure A-38 6-Inch, 47-Caliber High Explosive-Controlled Variable Time Projectile ...................................... A-29Figure A-39 6-Inch, 47-Caliber Illuminating Projectile ...................................................................................... A-30Figure A-40 6-Inch, 47-Caliber Armor-Piercing Projectile ................................................................................ A-30Figure A-41 6-Inch, 47-Caliber Gun Propelling Charge Assembly .................................................................... A-30Figure A-42 8-Inch, 55-Caliber High Capacity Projectile................................................................................... A-33

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Figure Title Page


Figure A-43 8-Inch, 55-Caliber Projectile High Explosive Controlled Variable Time .......................................A-34Figure A-44 8-Inch, 55-Caliber Common Projectile ...........................................................................................A-34Figure A-45 8-Inch, 55-Caliber Armor-Piercing Projectile .................................................................................A-34Figure A-46 8-Inch, 55-Caliber Gun Propelling Charge Assembly.....................................................................A-35Figure A-47 16-Inch, 50-Caliber High Capacity Projectile .................................................................................A-37Figure A-48 16-Inch, 50-Caliber High Capacity Controlled Variable Time Fuzed Projectile ............................A-37Figure A-49 16-Inch, 50-Caliber High Capacity Electronic Time Fuzed Projectile............................................A-38Figure A-50 16-Inch, 50-Caliber Antipersonnel Projectile..................................................................................A-38Figure A-51 16-Inch, 50-Caliber, Armor-Piercing Projectile ..............................................................................A-38Figure A-52 Fuze M75 (Point Detonating), Cross-Sectional View .....................................................................A-41Figure A-53 Primer MK 37 MODs 1 and 2 (Electric), Cross-Sectional View ....................................................A-42Figure A-54 Primer MK 38 MODs 1 and 2 (Electric), Cross-Sectional View ....................................................A-44Figure A-55 Primer MK 39 MODs (Electric), Cross-Sectional View.................................................................A-45Figure A-56 Primer MK 40 MODs 1 and 2 (Electric), Cross-Sectional View ....................................................A-47Figure A-57 Primer MK 35 MOD 1 (Case Combination), Cross-Sectional View ..............................................A-48Figure A-59 Typical External Tracer, Cutaway View .........................................................................................A-49Figure A-58 Typical Internal Tracer, Cutaway View ..........................................................................................A-49Figure A-60 3-Inch, 50-Caliber Ammunition Data..............................................................................................A-51Figure A-61 3-Inch, 50-Caliber, High Explosive Projectile ................................................................................A-53Figure A-62 3-Inch, 50-Caliber, High Capacity Projectile, MK 33.....................................................................A-54Figure A-63 3-Inch, 50-Caliber, Antiaircraft High Capacity Projectile, MK 27 .................................................A-54Figure A-64 3-Inch, 50-Caliber Armor-Piercing Projectile .................................................................................A-55Figure A-65 3-Inch, 50-Caliber Illuminating Projectile.......................................................................................A-55Figure A-66 3-Inch, 50-Caliber Nonfragmenting, Target Practice Projectile......................................................A-55Figure A-67 3-Inch, 50-Caliber Propelling Charge .............................................................................................A-56Figure A-68 3-Inch, 50-Caliber Dummy Cartridge .............................................................................................A-56Figure A-69 Propellant Grain Web Locations .....................................................................................................A-57Figure B-1 Use of Vise Grip Nose Fuze Adapter Wrench on Projectile .............................................................B-1Figure B-3 Typical Auxiliary Fuze Setting Wrench............................................................................................B-2Figure B-4 Fuze Setter M27.................................................................................................................................B-2Figure B-2 Fuze Wrenches ..................................................................................................................................B-2Figure B-5 Fuze Setter M36.................................................................................................................................B-4Figure B-6 Fuze Setter M36 Major Components.................................................................................................B-5Figure B-7 MODE Switch TI and PD Positions ..................................................................................................B-6Figure C-1 M732 Controlled Variable Time - Radio Frequency Proximity Fuze...............................................C-2Figure C-2 M732 Controlled Variable Time - Radio Frequency.........................................................................C-3Figure C-3 MK 30 MOD 5 Point Detonating Fuze .............................................................................................C-4Figure C-4 MK 67 MOD 3 Propelling Charge ....................................................................................................C-5Figure C-5 MK 80 All Up Round ........................................................................................................................C-7Figure C-6 MK 91 All Up Round ........................................................................................................................C-8Figure C-7 MK 92 All Up Round ........................................................................................................................C-9Figure C-8 MK 100 All Up Round ....................................................................................................................C-10Figure C-9 MK 108 All Up Round ....................................................................................................................C-11

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Figure C-10 MK 127 All Up Round.................................................................................................................... C-12Figure C-11 MK 156 All Up Round.................................................................................................................... C-13Figure C-12 MK 157 All Up Round.................................................................................................................... C-14Figure C-13 MK 158 All Up Round.................................................................................................................... C-15Figure C-14 MK 160 All Up Round.................................................................................................................... C-16Figure C-15 MK 173 All Up Round.................................................................................................................... C-17Figure C-16 MK 393 MOD 0 Mechanical Time/Point Detonating Fuze............................................................ C-18Figure C-17 MK 399 MOD 1 Point Detonating/Delay Fuze .............................................................................. C-19Figure C-18 MK 404 MOD 2 Variable Time Infrared (VT-IR) ......................................................................... C-20Figure C-19 MK 407 MOD 1 Point Detonating/Delay Fuze .............................................................................. C-22Figure C-20 MK 418 MOD 0 Variable Time - Radio Frequency Proximity Fuze ............................................. C-24Figure C-21 MK 419 MOD 0 Multi-Function Fuze (MFF) ................................................................................ C-26

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Table Title PageTable 1-1 List of Reference Publications .......................................................................................................... 1-3Table 1-2 List of Abbreviations and Acronyms ................................................................................................ 1-4Table 3-1 M50 Series Ammunition Data .......................................................................................................... 3-3Table 3-2 M90 Series Ammunition Data (Maximum Length - 7.23 Inches) .................................................... 3-5Table 3-3 M200 Series Ammunition Data (Maximum Length - 7.25 Inches) .................................................. 3-6Table 3-4 25 Millimeter Ammunition Data ...................................................................................................... 3-9Table 3-5 30 Millimeter Ammunition for MK 46 Gun Weapons System ...................................................... 3-11Table 3-6 30 Millimeter Ammunition Data .................................................................................................... 3-12Table 3-7 40 Millimeter Ammunition Data .................................................................................................... 3-16Table 3-8 57 Millimeter Ammunition Data .................................................................................................... 3-17Table 3-9 57 Millimeter 70 Caliber Mode and Target Type ........................................................................... 3-18Table 3-10 57 Millimeter Explosive Weights ................................................................................................... 3-18Table 3-11 76 Millimeter Ammunition Data .................................................................................................... 3-21Table 3-12 5-Inch, 54-Caliber Projectile Fuze Information Indexed by MK and MOD .................................. 3-25Table 3-13 5-Inch, 54-Caliber Projectiles Indexed by DODIC and NSN ......................................................... 3-26Table 3-14 5-Inch, 54-Caliber Projectile Fuze Information Indexed by DODIC and NSN ............................. 3-28Table 3-15 Current Fleet Issue 5”/54 Caliber Propelling Charges .................................................................... 3-34Table 4-1 VT-RF Fuzes MK 417 and MK 418, Characteristics ..................................................................... 4-27Table 4-2 VT-RF Fuze MK 73, Characteristics .............................................................................................. 4-28Table 4-3 CVT-RF Fuze M728, Characteristics ............................................................................................. 4-52Table 4-4 CVT-RF Fuze and Adapter Assembly MK 360 , Characteristics ................................................... 4-53Table 4-5 M732 CVT Fuze Functions for Various Settings ........................................................................... 4-73Table 4-6 M513/M514 CVT Fuze Functions for Various Settings ................................................................. 4-74Table 4-7 M728 CVT Fuze Functions for Various Settings ........................................................................... 4-75Table 4-8 Controlled Variable Time Fuze M728 Functions for Various Settings .......................................... 4-75Table 4-9 Fuze Setting Message Format ......................................................................................................... 4-97Table 4-10 Overhead Electrical Safety Features ............................................................................................... 4-99Table 4-11 Safety Time Line for 5”/54 Service Charge Firing ......................................................................... 4-99Table 4-12 3P Fuze No-Arm and All-Arm Ballistic Thresholds .................................................................... 4-107Table 4-13 3P Fuze Ballistic Function Threshold ........................................................................................... 4-107Table 4-14 Characteristics of Modern Auxiliary Detonating Fuzes ............................................................... 4-109Table 5-1 Primers by Mark and MOD with Assignment to Gun or Use ........................................................... 5-1Table 6-1 Relative Grain Sizes by Gun Caliber ................................................................................................ 6-5Table A-1 40 Millimeter Ammunition Data ......................................................................................................A-8Table A-2 5-Inch, 38-Caliber Projectile Data ..................................................................................................A-15Table A-3 5-Inch, 38-Caliber Projectile Data ..................................................................................................A-24Table A-4 6-Inch, 47-Caliber Projectile Data ..................................................................................................A-28Table A-5 5-Inch, 38-Caliber Projectile Data ..................................................................................................A-30Table A-6 8-Inch, 55-Caliber Projectile Data ..................................................................................................A-32Table A-7 8-Inch, 55-Caliber Propelling Charge Data ....................................................................................A-34Table A-8 16-Inch, 50-Caliber Projectile Characteristics Data .....................................................................A-36Table A-9 16-Inch, 50-Caliber Propelling Charge Data ..................................................................................A-40Table A-10 Historic Primers by Mark and MOD with Assignment to Gun or Use ...........................................A-42Table A-11 3-Inch, 50-Caliber Ammunition Data .............................................................................................A-51Table A-12 Relative Grain Sizes by Gun Caliber ..............................................................................................A-57Table B-1 Fuze Wrenches and Setters Used with Navy Gun Ammunition .......................................................B-3

LIST OF TABLES

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Table Title Page

LIST OF TABLES (Continued)

Table B-2 Fuze Setter M36 Physical Characteristics ........................................................................................ B-6Table B-3 Time Required to Charge Fuze Setter Battery ................................................................................. B-7

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The following are general safety precautions that are not related to any specific procedures and there-fore do not appear elsewhere in this publication. These are recommended precautions that personnel must understand and apply during many phases of operation and maintenance.

UNAUTHORIZED USES OF AMMUNITION

No ammunition or explosive assembly shall be used in any gun or equipment for which it is not desig-nated, nor shall any explosive of pyrotechnic device be manufactured, purchased or assembled for use in displays, demonstrations, tests or for any other purpose unless authorized by the Naval Sea Systems Com-mand.

DANGER, WARNING AND CAUTION STATEMENTS

WARNING and CAUTION statements have been strategically placed throughout this text to operating or maintenance procedures, practices or conditions considered essential to the protection of personnel (WARNING) or equipment and property (CAUTION). A WARNING or CAUTION will apply each time the related step is repeated. Prior to starting any task, the WARNINGS or CAUTIONS included in the text for that task will be reviewed and understood. Refer to the materials list figure at he beginning o the appropriate manual section for material used during maintenance of this equipment. The detailed warnings for hazardous material only are listed separately in the safety summary as the

HAZARDOUS MATERIALS WARNINGS

Warnings for hazardous material in this manual are designed to warn personnel of hazards associated with items when they come in contact with them during actual use. For each hazardous material used, a material safety data sheet is required to be provided and available for review by users. Consult your local safety and health staff concerning any questions on hazardous chemicals, MSDSs, personal protective equipment requirements, and appropriate handling and emergency procedures.

SAFETY SUMMARY

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CHAPTER 1

INTRODUCTION

1-1. SAFETY SUMMARY All personnel concerned with the receipt,

issue, handling, transporting, stowage, installation, and operation of Navy surface gun ammunition described in this publication must understand the procedures and safety precautions set forth herein. The following information appears in Chapter 2 of this publication and is repeated here for emphasis.

1-1.1. Fleet Inspection of Projectile Prior to Use. Fleet users shall check for damage to gas check seals that may have occurred during han-dling, transportation, and storage subsequent to issue by an ammunition activity. Ensure the fol-lowing:

a. Gas check seal is present.

b. Gas check seal is free of cuts, tears, or gouges that expose the lead core.

c. Gas check seal is flush with or below base fuze or plug surface.

Ammunition with any of the above defects should be marked as defective and should be turned in at the earliest opportunity. A message report should be made to the Naval Sea Systems Command (NAVSEASYSCOM), with copies to the Naval Weapons Station (WQEC), Concord, California, and the Crane Division, Naval Surface Warfare Center, Crane, Indiana (NAVSURFWAR-CENDIV Crane), giving ammunition lot identifica-tion, nature of defect, and any background information on the cause, if available. For criteria to be used when inspecting gas check seal or for pre-1970 (uninspected, unsuffixed) loaded ammu-nition, refer to Chapter 2 of this manual.

1-1.2. Unserviceable Suspended, and Limited-Use Ammunition. For information pertaining to the degree of serviceability of ammunition and ammunition components used by the Navy, Marine Corps, and Coast Guard, refer to NAVSUP P-801. It contains a listing of items, usually by lot number, that are not suitable for unrestricted use in the man-ner for which they were designed. In cases where it has been determined that an ammunition item may endanger life or property, rapid promulgation

of the information is accomplished by a message, Notice of Ammunition Reclassification (NAR). NARs are incorporated in NAVSUP P-801 as changes to that publication are made. Immediately upon receipt of any change in the status of ammu-nition, all commands shall determine whether stocks on hand include any of the affected lots or types. Action shall be taken to ensure that the use or issue of the affected ammunition is consistent with the newly assigned classification.

1-1.3. Unauthorized Uses of Ammunition. No ammunition or explosive assembly shall be used in any gun or equipment for which it is not desig-nated; nor shall any explosive or pyrotechnic device be manufactured, purchased, or assembled for use in displays, demonstrations, tests, or for any other purpose unless authorized by NAVSEASYS-COM.

1-2. REPORTING OF EXPLOSIVE MIS-HAPS

Every accident, incident, or malfunction involving ammunition and explosive operations shall be investigated and reported in accordance with OPNAVINST 5102.1.

1-3. SCOPE This manual provides general and specific

information concerning the description and assem-bly of Navy surface gun ammunition under the cognizance of NAVSEASYSCOM and identified as 2T cognizance items in TW010-AA-ORD-30. This manual covers Navy surface gun ammunition in the following sizes:

a. 20 millimeter (mm)

b. 25mm

c. 30mm

d. 40mm (excluding 40mm grenades covered in SW010-AD-GTP-010)

e. 57mm

f. 76mm, 62 caliber

g. 3-inch, 50 caliber

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h. 5-inch, 38 caliber

i. 5-inch, 54 caliber The information given includes general char-

acteristics, specific data, means of identification, precautions in handling and use, and packing and shipping references. Descriptions and data are pro-vided for gun ammunition components. These components include explosives, projectiles, fuzes, primers, tracers, and propelling charges. All cur-rently available Department of Defense identifica-tion codes (DODICs) are included for projectiles and propelling charges. Definitions are provided, and classifications are described and explained. Similar information on 16-inch, 50 caliber gun ammunition is given in Appendix A.

1-4. INTENDED USE This publication is intended for use by all

Navy personnel responsible for the procurement, preparation, handling, and tactical use of Navy gun-type ammunition.

1-5. ARRANGEMENT OF CONTENT Specific information concerning ammunition

assemblies, fuzes, primers, tracers, and explosives is presented in six separate chapters and two appendixes as follows:

Chapter 1: Introduction to contents and informa-tion of a general nature including safety, reporting of accidents and mal-functions, and reference publications.

Chapter 2: Introductory information on gun ammunition including classification, identification, definitions of ammuni-tion components, and a guide to the choice of fuze and projectile combina-tions.

Chapter 3: Resumes of the characteristics of the complete round presented according to the size of gun, the mark and mod num-bers, and the type of ammunition.

Chapter 4: Information on fuzes and tracers arranged by mark and mod numbers.

Chapter 5: Information on primers arranged by mark and mod numbers.

Chapter 6: Information on explosives and propel-lants as related to gun ammunition.

Appendix A: Historical Data

Appendix B: Fuze Setters and Wrenches

Appendix C: Ammunition and Fuze Data SheetsA numerical DODIC Index, a Mark Index, and

an Alphabetical Index are included at the end of this manual.

1-6. REFERENCE DATA The publications listed in Table 1-1 provide

additional information for the ordnance items used in this manual. Table 1-2 lists the abbreviations and acronyms used.

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Table 1-1 List of Reference Publications

PUBLICATION TITLE

MIL-HBK-145 Military Handbook, Fuze Catalog, Procurement Standards and Development Fuzes

MIL-STD-333 Fuze, Projectile and Accessory Contours for Large Caliber Armaments

MIL-STD-709 Ammunition Color Coding

MIL-STD-1168 Ammunition Lot Numbering and Ammunition Data Card

MIL-STD-1316 Fuze Design, Safety Criteria for

MIL-STD-1323/187 Unit Load For Underway Replenishment Cartridge, 20MM, M50 Series Belted With MK 7 or M-14 Links

NAVSEA OP 4, Volume 2 Ammunition Afloat

NAVSEA OP 5, Volume 1 Ammunition and Explosives Ashore

NAVSEA OP 1188 Range Tables Abridged for U.S. Navy Guns

NAVSEA OP 2211 Surface Rockets

NAVSEAINST 5400.57 Engineering Agent Selection, Assignment, Responsibility, Tasking and Appraisal

OPNAVINST 5102.1 Navy and Marine Corps Mishap and Safety Investigation Reporting and Record Keeping Manual

SW010-AD-GTP-010 Small Arms and Special Warfare Ammunition

SW010-AF-ORD-010 Identification of Ammunition

SW020-AE-SAF-010 Safety Surveillance of Navy Gun Propellant

NAVSUP P-724 Conventional Ordnance Stockpile Management Volume I and II

NAVSUP P-801 Ammunition, Unserviceable, Suspended, and Limited Use

NAVSUP P-802 Navy Ammunition Logistic Code

NAVSUP P-803 Navy Stock List of Conventional Ammunition

NAVSUP P-804 Data Supplement

NAVSUP P-805 Navy and Marine Corps Conventional Ammunition Sentencing Receipt, Segregation, Storage and Issue Sentencing

NAVSUP P-806 Inspection Requirements for Receipt, Segregation, Storage and Issue of Navy and Marine Corps Conventional Ammunition (Segregation Requirements)

NAVSUP P-807 Navy and Marine Corps Conventional Ammunition Sentencing; Fleet Sentencing

STANAG 2916 Nose Fuze Contours and Matching Projectile cavities for Artillery and Mortar Projectiles

WS 18782 Painting, Marking, and Lettering of Naval Gun Ammunition

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Table 1-2 List of Abbreviations and Acronyms

ABBREVIATION/ACRONYM TITLE

3P Pre-Fragmented, Programmable, Proximity

AA Antiaircraft

AAC Antiaircraft, Common

AD Auxiliary Detonating (Fuze)

ADL Automated Data List

AID Altered Item Drawing

ALN Ammunition Lot Number

AP Armor-Piercing

AP-DS Armor-Piercing, Discarding Sabot

APERS Antipersonnel

APFSDS-T Armor-Piercing, Fin Stabilized, Discarding Sabot, Traced

AP-T Armor-Piercing Tracer

AUT Autonomous

BD Base Detonating (Fuze)

BL Blind Loaded

BL-P Blind Loaded and Plugged

BL-T Blind Loaded and Tracer

CC Case, Combination

CE Case, Electric

CET Case, Electric (Test)

Chaff Chaff Dispensing

CIWS Close-In Weapons System

CNO Chief of Naval Operations

COM Common

CP Case, Percussion

CTG Cartridge

CVT Controlled Variable Time (Fuze)

CVT-RF Controlled Variable Time-Radio Frequency

DASD Delayed Arming Safety Device

Dl Dark Ignition

DL Data List

DLSC Defense Logistics Services Center

DLY Delay

DoD Department of Defense

DODIC Department of Defense Identification Code

DS Discarding Sabot

DOT Department of Transportation

ECM Electrocountermeasure

EFCT Electronic Firing Circuit Tester

EFV Expeditionary Fighting Vehicle

ELC Enhanced Lethality Cartridge

EMI Electromagnetic Interference

ERGM Extended Range Guided Munition

ET Electronic Time (Fuze)

FAAT First Article Acceptance Test

FC Fire Control/Fire Controlman

FCL Fuze Cavity Liner

FCS Fire Control System

FO Foreign Ordnance

FS Fin Stabilized

FSC Federal Supply Class

FSN Federal Stock Number

GCS Gas Check Seal

GFC Gun Fire Control

GFCS Gun Fire Control System

GFS Gun Fire Support

GL Grand Lot

GM Gun Mount/Gunner’s Mate

GP Guided Projectile

Table 1-2 List of Abbreviations and Acronyms (Continued)


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GWS Gun Weapons System

HC High Capacity

HC-ET High Capacity-Electronic Time

HC-PD High Capacity-Point Detonating

HC-PD/DNP High Capacity, Point Detonating/Dummy Nose Plug

HC-S High Capacity-Special

HE High Explosive

HE-3P High Explosive-Pre-Fragmented, Programmable, Proximity

HE-CVT High Explosive-Controlled Variable Time

HE-ET High Explosive-Electronic Time

HEI High Explosive Incendiary

HEI-P High Explosive Incendiary-Plugged

HEI-P-NP High Explosive Incendiary-Plugged, Dummy Nose Plug

HE-IR High Explosive-Infrared

HEI-SD High Explosive Incendiary-Self-Destruct

HEI-T High Explosive Incendiary- Tracer

HEIT-DI-SD High Explosive Incendiary Tracer, Dark Ignition, Self-Destruct

HEIT-NSD High Explosive Incendiary Tracer, Non-Self-Destruct

HEIT-SD High Explosive Incendiary Tracer, Self-Destruct

HE-MT High Explosive-Mechanical Time

HE-MT/PD High Explosive-Mechanical Time/Point Detonating

HE-P High Explosive-Plugged



HE-PD High Explosive-Point Detonating

HE-PD/D High Explosive-Point Detonating/Delay

HE-SD High Explosive-Self-Destruct

HET High Explosive Tracer

HET-SD High Explosive Tracer-Self-Destruct

HE-VT High Explosive, Variable Time

HE-VT-NSD High Explosive, Variable Time, Non-Self-Destruct

HE-VT-SD High Explosive, Variable Time, Self-Destruct

Hl-FRAG High Fragmentation

HMX Cyclotetramethylenetetranitramine

HOB Height of Burst

HSMST High-Speed Maneuvering Surface Target

ICM Improved Conventional Munition

ILLUM Illuminating

INC Incendiary

IR Infrared

KE-ET Kinetic Energy-Electronic Time

LAT Lot Acceptance Test

LC Lock, Combination

LCT Lock, Combination (test)

LD List of Drawings

LD Low Drag

LOVA Low Vulnerability Ammunition

M Army Component Designation

MF Multi-Function

MFF Multiple Function Fuze

MIG Magnetic Induction Generator



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MIL-SPEC Military Specification

MIL-STD Military Standard

MK Mark

MOD Modification

MP Multipurpose

MPLD-T Multipurpose Low Drag Traced

MT Mechanical Time (Fuze)

NACO Navy Cool

NALC Navy Ammunition Logistics Code

NAR Notice of Ammunition Reclassification

NATO North Atlantic Treaty Organization

NAVSEA OP Ordnance Pamphlet

NAVSEASYSCOM Naval Sea Systems Command

NC Nitrocellulose

NCB National Codification Bureau

NG Nitroglycerin

NGFS Naval Gun Fire Support

NIIN National Item Identification Number

NMOS Nitride Metal Oxide Semiconductor

NONFRAG Nonfragmenting

NQ Nitroguanidine

NSD Non-Self-Destruct

NSN National Stock Number

NSWC Naval Surface Warfare Center

OD Ordnance Data

OR Ordnance Requirement

PC Percussion Cap

PCE Primer Cap, Electric

PD Point Detonating (Fuze)



PD/D Point Detonating/Delay (Fuze)

PETN Pentaerythritoltetranitrate

Poly Plug Polyurethane Plug

POP Performance-Oriented Packaging

PPD Production Packing Depth

Prop Chrg Propelling Charge

PROX Proximity (Fuze)

PRPLNT Propellant

PWP Plasticized White Phosphorus

RAP Rocket Assisted Projectile

RCS Radar Cross Section

RDX Cyclotrimethylenetrinitramine

RF Rapid Fire/Radio Frequency

RFM Rain Fix Modification

RFSD Rear Fitting Safety Device

S&A Safety and Arming

SAP Semi-Armor-Piercing

SCF Switched Capacitor Filter

SD Self-Destruct

SF Slow Fire

SP Smokeless Powder

SPC Smokeless Powder Stabilized by Ethyl Centralite

SPCC Ships Parts Control Center

SPCF Smokeless Powder, Stabilized by Ethyl Centralite, Flashless

SPCG Smokeless Powder, Stabilized by Ethyl Centralite, and including Nitroglycerin and Nitroguanidine

SPD Smokeless Powder Stabilized by Diphenylamine



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SPDB Smokeless Powder, Stabilized by Diphenylamine, and Blended

SPDF Smokeless Powder, Stabilized by Diphenylamine, and Flashless

SPDN Smokeless Powder, Stabilized by Diphenylamine, and Nonhygroscopic

SPDW Smokeless Powder, Stabilized by Diphenylamine, and Reworked

SPDX Smokeless Powder, Stabilized by Diphenylamine, and Water Dried

SPWF Smokeless Powder, Reworked, and Flashless

SQ Superquick

T Traced

Tl Time Initialized

TNT Trinitrotoluene



TP Target Practice

TP-Puff Target Practice (puff)

TP-VT-NSD Target Practice, Variable Time, Non-Self-Destruct

TP-VT-SD Target Practice, Variable Time, Self-Destruct

VT Variable Time, i.e., a fuze activated by its proximity to the target; also called “proximity” and “influence”

VT-IR Variable Time-Infrared

VT-NONFRAG Variable Time, Nonfragmenting

VT-RF Variable Time-Radio Frequency

WP White Phosphorus

WQEC Weapons Quality Engineering Center

WR Weapons Requirement

WS Weapons Specification



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CHAPTER 2

AMMUNITION INFORMATION

2-1. SCOPE This chapter covers identification and classifi-

cation of gun ammunition; definitions and descrip-tions of components; associated terms and ammunition containers; selection of projectiles and fuzes for attack of ship, shore, and air targets; and procedures for inspection prior to issue for projec-tiles with base fuzes and/or base fuze hole plugs. The procedures for nose fuze removal and/or replacement and fuze setters and wrenches used with Navy surface gun ammunition are in Appen-dix B.

2-2. IDENTIFICATIONNavy-adopted items of material that have been

type classified according to TW010-AA-ORD-010/11-1-116A, Classes Q and R, are officially identified by logistical terms. Each ammunition item is identified by its approved nomenclature, its identification number, contract number, its lot number (including the manufacturer and year and month of manufacture), and its gross weight. This information is stenciled either on the item itself, on its shipping container, or on both. When a basic change in design is made, a new identification number is assigned. When a minor alteration or modification is made, a new MOD number is assigned.

2-2.1. Navy Item Identification. Ammunition items designed and produced for the Navy are identified by marks and mods; for example: Primer, MK 14 MOD 0 (Percussion). An improved (reliability, safety, and/or life) modification of this item would result in its being identified as MK 14 MOD 1.

2-2.2. Army Item Identification. When the Navy procures ammunition items that were designed and produced for the Army, the originally assigned Army identification number remains with the item. In an item such as 20mm M210A car-tridge, the M corresponds to the model and the A to the modification. A minor modification of this cartridge would result in its being identified as M210A1.

2-2.3. Items without Identification Numbers. Some ammunition items do not have Navy or Army item identification numbers and are identi-fied by their nomenclature and the drawing num-ber.

2-2.4. Standard Department of Defense Nomenclature and Numbering. A standard nomenclature and numbering system has been established by DoD. This system is a four-digit, alphabetic/numeric code that is either a Depart-ment of Defense identification code (DODIC) assigned by Defense Logistics Services Center (DLSC) or a Navy ammunition logistics code (NALC) assigned by Naval Inventory Control Point (NAVICP). The national stock number (NSN) has replaced the Federal stock number (FSN). There is a different NSN for each item in supply. The first four digits in the NSN are the Federal supply class (FSC), which groups similar type items into classes. The next two digits are the National Codification Bureau (NCB) code number designating the North Atlantic Treaty Organization (NATO) country that catalogs the item. The last seven digits combined with the NCB code number (two digits) are designated as the national item identification number (NIIN).

2-2.5. Ammunition Lot Numbers. When ammunition is manufactured, an ammunition lot number is assigned according to specifications. As an essential part of the lettering, the lot number is stamped or marked on the item, size permitting, as well as on all packing containers. There are pres-ently two ammunition lot numbering systems in the ammunition inventory. The newest lot numbering system was implemented by the Navy in 1978, so there is ammunition still identified by the old ammunition lot numbering system. Both systems are described in the following paragraphs.

2-2.5.1. Current Ammunition Lot Numbering System. For all ammunition end items and their components, the ammunition lot number consists of a manufacturer’s identification symbol, a numeric code showing the year of production, an alpha code representing the month of production, a

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lot interfix number followed by a hyphen, a lot sequence number, and, when necessary, an alpha character used as an ammunition lot suffix to denote a reworked lot. The ammunition lot num-ber does not exceed 14 characters in length, and no characters are separated by spaces. The minimum number of characters used is 13. If a one- or two-character manufacturer’s identification code is used, the remaining positions of the three-character field is filled by dashes (–); e.g., A– and AB–. The following illustrates the construction of an ammu-nition lot number:

CRA75D001-024Bwhere:

CRA = Manufacturer’s identification symbol75 = Two-digit numeric code identifying

the year of production (1975)D = Single alpha code signifying the

month of production (April)001 = Lot interfix number024 = Lot sequence numberB = Ammunition lot suffix (the alpha suf-

fix identifying reworked lots).Exceptions to the foregoing system for num-

bering ammunition lots are given in MIL-STD-1168, Section 5.

2-2.5.2. Old Ammunition Lot Numbering System. The old ammunition lot numbering sys-tem consists of the ammunition lot number symbol (ALN), followed by a two- to three-letter prefix, a sequential lot number, a one- to three-letter manu-facturer’s symbol, a two numeral group and possi-bly a lot suffix. An example of an ALN is the following:

ALN BE-374-HAW-78where:

BE = 5-inch, 38 caliber projectile374 = 374th lot of projectiles assembledHAW = NAD Hawthorne assembly activity78 = Assembled during the year of 1978.

2-2.5.3. Prefix Designation. The two- to three-letter prefix designation identifies the size and type of ammunition item. A prefix designation having a final letter “R” denotes renovated items.

2-2.5.4. Sequential Lot Number. The one- to four-character group following the prefix indicates the sequential lot number of that particular type produced by an activity during the calendar year. This group consists of numbers 1 through 9999.

2-2.5.5. Manufacturer’s Letters and Num-bers. From one to three letters identify the ord-nance activity that assembled the ammunition item. Following the symbols is the final numerical group, indicating the last two digits of the calendar year of assembly.

2-2.5.6. Lot Suffix. An alpha character, follow-ing the year of assembly, usually indicates some type of special screening was performed.

2-2.6. Color Codes, Markings, and Lettering. The system of identifying ammunition by the use of color codes, marking, and lettering is intended to be a ready identification to determine the explosive loads and hazards presented by the identified items. A color-coding system is employed to indi-cate the primary use of ammunition, the presence of a hazardous (explosive, flammable, irritant, or toxic) filler, and/or the color of tracers, dye loads, and signals. Color codes for ammunition of 20 mm and larger are contained in MIL-STD-709, SW010-AF-ORD-010, latest revisions, and WS 18782. The lettering, stenciled or stamped on ammunition, includes all the information necessary for complete identification and is marked in compliance with UN International and Performance Oriented Pack-aging (POP) Standards, NATO standards, and Department of Transportation (DOT) regulations. In addition to standard nomenclature and lot num-bers, lettering may include such information as the mark and mod, the type of fuze, and the weapon in which the item is fired.

2-3. CLASSIFICATION OF GUN AMMUNI-TION

2-3.1. Introduction. There are two ways to clas-sify gun ammunition. It may be classified by size of gun or by assembly.

2-3.2. Classification by Size of Gun. Gun ammunition is most commonly classified by the size of the gun in which it is used. In addition to designations of bore diameter, such as 20mm or

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5 inches, the length of the gun bore in calibers is also used as a means of classification. Thus a 5-inch, 54 caliber projectile is one used in a gun hav-ing a bore diameter of 5 inches and a barrel length of 54 times 5 inches, or 270 inches.

2-3.3. Classification by Assembly. The two types of ammunition classified by assembly are shown in Figure 2-1. A third type, separate loading (bagged) gun ammunition, is no longer used in the Fleet. Historical information can be found in Appendix A.

2-3.3.1. Fixed Ammunition. This class applies to ammunition that has the cartridge case crimped around the base of the projectile. The primer is assembled in the cartridge case. The projectile and the cartridge case containing the primer and pro-pellant charge all form one unit as a fixed round of ammunition. Small caliber guns and guns through 76mm, 62 caliber use fixed ammunition.

2-3.3.2. Separated Ammunition (Semi-Fixed).This class applies to ammunition that consists of two units: the projectile assembly and propelling charge assembly. Because of their physical size, they are stored separately and do not come together until they are loaded into the gun. The projectile assembly consists of the projectile body containing the load, and nose or base fuze, and auxiliary deto-

nating fuze, as applicable. The propelling charge assembly consists of the cartridge case, wear liner, primer, propellant charge, wad and distance piece (if needed), and a plug to close the open end of the cartridge case. Separated ammunition is produced for gun sizes 5 inches and larger.

2-4. GUN AMMUNITION COMPONENTS AND SHIPPING CONTAINERS

2-4.1. Introduction. The components of Navy surface gun ammunition are defined and described in the following paragraphs. These components include projectile, propelling charge, primer, car-tridge case, miscellaneous components and details, handling and shipping parts, and shipping contain-ers.

2-4.2. Projectile. The projectile is that compo-nent of ammunition that, when fired from a gun, carries out the tactical purpose of the weapon. While some types of projectiles are one piece, the majority of naval gun projectiles are assemblies of several components. All of the projectiles to be briefly discussed by classification in this chapter, and later by caliber in Chapter 3, have several com-mon features as described in the following para-graphs and as illustrated in Figure 2-2.

Figure 2-1 Types of Gun Ammunition: Fixed and Separated

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2-4.2.1. Projectile Components.

2-4.2.1.1. Ogive. The ogive is the curved for-ward portion of a projectile. The curve is deter-mined by a complex formula designed to give maximum range and accuracy. The shape of the ogive is generally expressed by stating its radius in terms of calibers. It may be a combination of sev-eral arcs of different radii.

2-4.2.1.2. Bourrelet. The bourrelet is a smooth, machined area that acts as a bearing surface for the projectile during its travel through the bore of the gun. Some projectiles have only one bourrelet (forward); the rotating band serves as the bearing surface in the rear. Other projectiles have one bourrelet forward and one or two aft, the aft one being located adjacent to and either forward and/or aft of the rotating band. Bourrelets are painted to prevent rusting.

2-4.2.1.3. Body. The body is the main part of the projectile and contains the greatest mass of metal. It is made slightly smaller in diameter than the bourrelet and is given only a machine finish.

2-4.2.1.4. Rotating Band. The rotating band is circular and made of commercially pure copper, copper alloy, or plastic seated in a scored cut in the aft portion of the projectile body. For minor and medium caliber projectiles, rotating bands are made of commercially pure copper or gilding metal, which is 90 percent copper and 10 percent zinc. Major caliber projectile bands are of cupro-nickel alloy, containing 2.5 percent nickel or nylon with a Micarta insert. As a projectile with a metal-lic band passes through the bore of the gun, a cer-

tain amount of copper is wiped back on the rotating band and forms a skirt of copper on the aft end of the band as the projectile leaves the muzzle of the gun. This is known as fringing and is prevented by cutting grooves, called cannelures, in the band or by undercutting the lip on the aft end of the band. These cuts provide space for the copper to flow into. The primary functions of a rotating band are (1) to seal against the escape of the propellant gas around the projectile, (2) to engage the rifling in the gun bore and impart rotation to the projectile, and (3) to act as a rear bourrelet on those projec-tiles that do not have a rear bourrelet. With copper-banded projectiles, some of the copper is left in the grooves of the barrel’s rifling. In some larger cali-ber guns, if left untreated, this copper may accumu-late after gun firing to prevent proper seating of the next projectile. A decoppering agent, currently lead, is added to the propelling charge to remove the copper with each firing.

2-4.2.1.5. Base. The base is the aft end of the projectile. A removable base plug is provided in projectiles that are loaded through this end. A fuze hole may be drilled and tapped in the center of this base plug. Projectiles with large openings in the nose for loading through that end require no base plug. In such cases, however, the solid base of the projectile may be drilled in the center to receive a base fuze or tracer if desired. The edge formed by the side walls and the base is usually broken slightly to give additional range. Some projectiles are tapered aft of the rotating band, a shape known as boat-tailed. Projectiles with plastic bands may have full caliber boat-tails for optimum aerody-namic shape.

2-4.3. Propelling Charges. Propelling charges are mixtures of energetic materials (low explo-sives) designed to propel projectiles from the gun to the target. The two assembly classifications of ammunition, fixed or separated, describe how the propelling charges interface with their projectiles. In fixed ammunition, the propelling charge and projectile are assembled together and are handled as one unit. In separated (semi-fixed) ammunition, the propelling charge(s) and projectile are assem-bled separately; they are stored and handled as sep-

Figure 2-2 Typical Projectile, External View

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arate units. Figures 2-3 and 2-4 are illustrations of typical fixed and separated propelling charges that are currently used in the Fleet.

2-4.3.1. Case Ammunition. Propelling charges for small and medium caliber guns are assembled with primer and powder enclosed in a container called a cartridge case. (All current Navy ammuni-tion is loaded in metallic cases of steel or brass. Some Army or Marine Corps. ammunition uses combustible cartridge cases of a material whose appearance is like a plastic-coated heavy card-board). Assembly of the entire charge in a single, rigid, protective case increases the ease and rapid-ity of loading and reduces the danger of flare-backs. Also, the case prevents the escape of gases toward the breech of the gun; it expands from the heat and pressure of the burning powder and forms a tight seal against the chamber. After the peak pressure has passed, it should relax to its original size so that it can easily be extracted from the gun chamber. The loading of case ammunition assem-blies is similar for both fixed and separated rounds up to the point at which the mouth of the case is sealed. In fixed ammunition (Figure 2-3) the case is crimped around the projectile on or aft of the rotating band; in separated ammunition (Figure 2-4) a closure plug is used. The term “cartridge” is usually used to mean a complete round of fixed ammunition, while propelling charge often refers only to the propelling charge for separated ammu-nition.

2-4.3.1.1. Reduced Charge. A reduced charge is a propelling charge intended to produce a veloc-ity below that achieved by a full charge for shoot-ing targets at close range. It is usually one in which less than the full charge of (an often differ-ent) propellant is placed in the cartridge case, and sometimes a different primer is used to accommo-date the short powder bed height.

2-4.3.1.2. Clearing Charge (aka Short Charge). A clearing charge can be used to remove a projectile after a firing malfunction. Malfunc-tions may include situation such as when a round fails to seat fully upon being rammed into the gun chamber (thus preventing closure of the breech), or when the propelling charge fails to function. The projectile may be removed by extracting the full-sized case, and then and loading the clearing charge (which is shorter), closing the breech, and then firing the charge to clear gun. The clearing charge contains just enough propellant to expel the projectile safely seaward away from the gun.

2-4.3.1.3. Saluting Charge. Saluting Charges are used to render honors. At this time, no Naval saluting charges are actually fired in actual guns but in ships employing 40mm fixtures (aka saluting batteries) for saluting. Since no projectile is involved in such firings, the charge consists of a cartridge case containing a propellant load (e.g., black powder) and a primer. Saluting charges for the 40mm guns are issued completely assembled, with no replacement components. Two types are available with different sound intensities. The lower intensity charge can be used where a lower output is desired, such as in confined areas.

2-4.4. Primer. A primer is a device for initiating the burning of the propellant charge in the chamber of a gun. Gun primers are classified by method of firing as percussion, electric, and combination. An additional classification can be by position of the primer such as lock or case (though there are no more lock primers in Fleet use). Primers are described in detail in Chapter 5 and Appendix A.

2-4.5. Cartridge. The term cartridge is used in this publication to mean a complete round of fixed ammunition. The propelling charge and projectile are assembled as one unit.

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Figure 2-3 Components of Propelling Charge in Case (Fixed) Ammunition

Figure 2-4 Components of Propelling Charge in Separated Ammunition

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2-4.6. Cartridge Case. Most of the cartridge cases used in the Fleet are made of steel. Brass cases have also been used. Brass case can be reused after reforming, sometimes as many as 30 reuses, but concerns about sources of brass, as well as logistic concerns, have made steel the more desirable material for use. Most steel cases are currently manufactured using a deep-drawn pro-cess. The sidewall of the cartridge cases is often given a light coating of wax to aid in extraction from the gun; particularly for propelling charges used in large caliber ammunition. Spiral wrap steel cartridge cases have been developed as an alternate case for a variety of uses, including propelling charges used in 5-inch, 38 caliber, guns, propelling charges use with 76mm ammunition (as well as for various Army propelling charges). A typical spiral wrap cartridge case consists of three components, a steel base, a sheet steel body, and a lock ring. When the propelling charge is launched, the pres-sure reduces and the case returns to the prefire shape for extraction. Currently, no spiral wrap cases are approved for Fleet use.

2-4.7. Explosive. An explosive is a material that can undergo very rapid self-propagating decompo-sition or combustion releasing large volumes of highly heated gases that exert pressure on the sur-rounding medium. Explosives are described in detail in Chapter 6.

2-4.8. Fuze. The fuze is a device designed to ini-tiate the payload of a projectile at a given time or position. The fuzing system comprises one or sev-eral fuzes. It is especially designed to maintain the projectile in a safe condition until it is fired from a gun, to arm during flight, and to function the pay-load as intended at the proper point relative to the target. The different types of fuzes include mechanical and electronic time, auxiliary detonat-ing, proximity, impact (nose or base), and some with combination features such as mechanical time with point detonating backup. Fuzes are described in detail in Chapter 4.

2-4.9. Tracer. A tracer is a pyrotechnic device that is ignited when the gun is fired and burns dur-ing the projectile flight so that it may be visually observed in its trajectory. A tracer may be integral with the projectile body or base fuze, or it may be a

separate item that is threaded into place in the base of the projectile. Tracers are described in detail in Appendix A.

2-4.10. Propellant. A propellant (low explosive) is a chemical composition designed to burn at a reproducible, controllable (though fast), and prede-termined rate. The function of a propellant is gen-eration of gaseous products that provides a propulsive force. The propellants of main concern in this publication are black powder and smokeless powder. Refer to Chapter 6 for more detail.

2-4.11. Miscellaneous Components. Miscella-neous components are those that are used in the assembly of gun-type ammunition but not covered in other categories assigned in this manual. They are illustrated in Figure 2-5.

2-4.11.1. Adapters. Adapters are used with pro-jectiles to join auxiliary detonator and nose fuzes. They are also used to connect the nose fuze to the projectile.

2-4.11.2. Wad/Wad Assembly. A wad is usually a cylindrical polyethylene block. Wad assemblies are polyethylene blocks assembled to one or more cardboard disks. The wad or wad assembly is installed close against the propellant to keep the propellant from shifting during transportation, stor-age and handling.

2-4.11.3. Distance Piece. The distance piece is a rectangular piece of cardboard folded into a pris-matic shape. When the top of the propellant bed is quite a bit lower than the mouth of the case, it is inserted between the wad and the plug or projectile to prevent shifting of the propellant bed during shipment and handling.

2-4.11.4. Lead Foil/Decoppering Agent. Occa-sionally, lead foil is installed in propelling charges as a decoppering agent. A decoppering agent is a chem-ical compound that helps remove copper from the bore of the gun barrel. The copper would have been deposited on bore from the rotating bands of projec-tiles and is undesirable. Some propelling charges contain propellant that have a lead salt in formulation which serves as a decoppering agent and the foil is not used. Newer propellant formulations are using lead-free compounds as decoppering agents.

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Figure 2-5 Miscellaneous Gun Ammunition Components and Details

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2-4.11.5. Closure Plug. In separated ammuni-tion (e.g. 5-inch), a closure plug seals the end of the cartridge case; it may also support the projectile if the two are moved through the handling system of the gun together. Currently, Polyurethane is typ-ically used as the material for the closure plugs. The plugs for 5-inch clearing charges are usually an elastomeric material that is black in color. Older propelling charges, such as D324, used cork as the plug material. Some may be found in stor-age, but are no longer used.

2-4.11.5.1. Polyurethane Plugs. In current pro-duction cork closure plugs have been replaced by polyurethane closure plugs (Figure 2-6) because of difficulties in acquisition and processing of a cork material. Polyurethane is a readily available domestic material that is inexpensive and can be formulated to give almost any desired combination of properties. To date, two varieties of polyure-thane closure plugs are in service—rigid and elas-tomeric. Polyethylene plugs are being evaluated to replace the polyurethane plug.

2-4.11.6. Fuze Cavity Liner. This is a thin metal liner that is inserted in the fuze cavity of the projectile.

2-4.12. Handling and Shipping Parts. Handling and shipping parts are items used to protect or pro-vide support during handling, shipping, and storage of gun ammunition. Those items that are consid-ered serviceable are usually returned to an ammu-nition depot. They are packed in the prescribed manner and contents identified.

2-4.12.1. Spacers. Spacers are made of polyeth-ylene, polystyrene, cork, cardboard, or wood in various thicknesses and are placed inside the ends of cartridge tanks and powder tanks to prevent lon-gitudinal movement of the cartridge case or pow-der bag.

2-4.12.2. Cartridge Extractors. Cartridge extractors are light metal cups shaped to fit the base end of cartridge cases. They have a handle or a sash cord to facilitate removal of the cartridge case from the cartridge tank. The extractor pro-tects the primer in addition to providing a means of removing the case from the tank.

2-4.12.3. Waterproof Protective Caps. These are metal caps fitted to mating threads on the exte-rior of the nose of the projectile (Figure 2-7). The cap helps protect a nose fuze from moisture or shock by handling. These caps are attached to sep-arated and separate-loaded projectiles. The caps are installed at the depot and are removed just before the projectiles are loaded into the hoists aboard ship for firing. If a projectile is not fired, the waterproof protective cap should be reinstalled before sending the projectile to storage.

2-4.12.4. Projectile and Cartridge Nose Sup-ports. These are placed in a cartridge tank for fixed ammunition to support the projectile and pre-vent movement. They are lightweight tubes with flanges for positioning.

Figure 2-6 Typical Polyurethane Plug

Figure 2-7 Typical Waterproof Protective Cap

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NOTENAVSEA OP4 assigns to the end users of ammunition the responsibility for recovery and return of reusable details derived from the firing of an end round of ammunition. Refer to NAVSUP P-724, Chapter 4, Section 5 “Return and Control of Reusable Ammunition Material Details and Non-Reusable Expendable Cartridge Cases” for instructions on correct turn-in procedures.

2-4.12.5. Pallets and Pallet Adapters. The metal pallets and pallet adapters used for genera-tion of ammunition unit loads and general ammuni-tion handling are considered reusable or serviceable items which are to be returned to an ammunition depot upon the removal of the ammu-nition. Refer to NAVSUP P-724.

2-4.13. Ammunition Containers. The projectiles for separated and separate loading gun ammunition are not shipped in containers. The parts that are most susceptible to damage—nose fuzes and rotat-ing bands—are protected, respectively, by caps and grommets. Propelling charges for separated ammunition, bag charges, fixed ammunition, and some nose fuzes are shipped and stored in contain-ers. Propelling charges for separated ammunition and bag charges are packaged individually in tanks; small-caliber fixed ammunition is shipped collectively in boxes. Separate components, such as primers for gun firing circuit testing and bag gun loads, are shipped in hermetically sealed cans, a number of such cans being placed in a wood box. All gun ammunition components in their contain-ers may be assembled into unit loads on metal or wood pallets for handling with powered equip-ment.

2-4.13.1. Ammunition Boxes. Metal boxes (Fig-ure 2-8) with gasketed covers are used as contain-ers for 20-, 25-, 30- and 40mm ammunition. The covers are clamped to the boxes with latches or they may have hinges and latches.

2-4.13.2. Cartridge Tanks. The larger caliber fixed ammunition is shipped individually in car-tridge tanks. These steel or aluminum tanks (Fig-ure 2-9) are provided with reinforcing rings around their ends. The rings allow an interlocking

arrangement when stored horizontally in rows. The side walls are relatively weak and are not designed to support superimposed weight. The tops of the tanks are closed by a metal cover bear-ing on a rubber gasket. The cover has a bail to facilitate installation and removal. A length of wire attached to the cover and to the body of the tank prevents the cover from loosening. Usually, an inspection of this wire will indicate whether the tank cover is tightly secured. The tanks are airtight when properly closed. Tanks for fixed cartridges are provided with interior supports for the noses of the projectiles. The separate propelling charges for 5-inch ammunition are also shipped in tanks.

2-4.13.3. Powder Tanks. Powder tanks are fab-ricated of aluminum to reduce sparking danger and storage weight and to facilitate handling; however, some steel tanks with brass top rings are still in use. Each powder tank contains one or several powder bags. Powder tanks are constructed in the same manner as cartridge tanks; the requirements for airtightness are the same. All powder tanks have handling aids. Large tanks have lugs that fit slings; smaller ones have handles. Wrenches are supplied for tightening the covers on powder tanks. Only the wrench furnished for the particular tank should be used. A smaller wrench might not suffi-ciently seat the cover in the gasket; a larger one might carry away part of the cover or tank.

2-5. SELECTION OF PROJECTILES AND FUZES FOR DIFFERENT TARGETS

2-5.1. General Considerations. This section is written to provide a basic understanding of fuze/projectile/gun system capabilities against various types of targets. It is meant to be in unclassified general terms. This is not meant to replace or sup-plement any Fleet Tactical Guidance such as in NWP 3-20.32.

2-5.1.1. Fuzes. There are seven basic modern types of fuzes; the VT-RF, the VT-IR, the CVT-RF, the MT/PD, the PD/DLY, the ET and the MFF. Chapter 4 goes into great detail about the design of each of these types of fuzes and their predecessors. The following is a basic description of each type:

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a. The VT-RF is an active radio frequency fuze. Its action depends on the reflection of its transmitted signal from a target. The fuze is designed as an all-around fuze to trigger 30 feet from most targets including aircraft, missiles, ships, and the land or water surface. The fuze has a PD back-up if no target is detected. The detection radius is slightly reduced in the presence of sea clutter or electromagnetic interference (EMI). VT-RF fuzes may be susceptible to some countermea-sures and extraneous EMI. The fuze is armed and ready to fire by 500 yards from the gun.

b. The VT-IR is a passive IR fuze which operates only on the infrared spectrum detected in the exhaust gasses of jet and hot missile targets. It is not intended for use against non-powered mis-siles, propeller aircraft, or to detect the exhaust from ships’ stacks. The fuze provides a burst in the proximity of the target and has a PD back-up if no target is detected. The fuze detection pattern is a 30 degree, hollow cone oriented forward about the projectile flight axis. The fuze detection radius exceeds the lethal radius of the projectile. Target triggered bursts are typical out to a 100 foot radius. The fuze is armed and ready to fire by 500 yards

from the gun. VT-IR fuzes are highly reliable and relatively immune to countermeasures. VT-IR fuze effectiveness is not degraded when used in low-over-the-waves applications.

c. The CVT-RF is another active radio fuze similar to the VT-RF except it is designed to only provide a 30 foot burst on the land or water sur-face. It is not intended for use against air targets as its sensitivity is such that the round would have to be placed within a couple of feet of most threats to achieve an airburst. It operates only in the impact mode until a few seconds prior to the time set on the fuze, which is normally the estimated time of flight. The set time is automatically set by the gun mounts’ fuze setter or it can be set by hand. Once in flight, the fuze is RF quiet until a few seconds before the set time, at which time the radio circuits are activated and then it operates in the same man-ner as the VT-RF fuze with a PD back-up. This delayed turn-on provides extra protection against countermeasures and improves overhead safety. The shortest time at which the fuze can be ready to operate is approximately 3 seconds, this is achieved by setting the fuze to five seconds. Most fuzes in the Fleet have been preset to 5 seconds.

Figure 2-8 Typical Box-Type Containers 20 Millimeter Cartridge and 40 Millimeter Cartridge

20 Millimeter Cartridge 40 Millimeter

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Figure 2-9 Typical Tank-Type Container - 5-Inch, 54-Caliber Charge and 76mm, 62-Caliber Cartridge

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d. The MT/PD is a mechanical time fuze with a selectable and back-up PD feature. The mechan-ical timer has a clock assembly that functions the round at the set time. The MT/PD fuze provides either an airburst round or PD round that is immune to countermeasures. The set time is auto-matically set by the gun mounts’ fuze setter or it can be set by hand.

e. The PD/DLY detonates on impact unless set to delay, where it will penetrate a target and then detonate inside. The delay mode must be set by hand using a slot screwdriver. The PD/DLY is a reliable countermeasure proof fuze that can reli-ably penetrate approximately up through a quarter inch of steel.

f. The ET is an electronic time fuze. It func-tions the round at a selected time which is induc-tively programmed into the fuze by the gun mount’s inductive fuze setter just prior to firing the round. The timing increments of the ET fuze are 0.01 seconds, which is much more precise than the MT fuze.

g. The MFF is a multi-function fuze. It com-bines mutiple operational modes such as VT-RF, CVT-RF, ET and PD into one fuze. The mode and operational requirements are programmed into the fuze by the gun mount’s inductive fuze setter just prior to firing the round. This is the most versatile type of fuze and can be used for numerous engage-ment scenarios.

2-5.1.2. Gun System Capabilities. The three guns in the Fleet discussed in this section are the 5”/54, 5”/62 and the 76mm. There are a few basic differences and a few commonalities to these guns. Basically the 5”/54 and 5”/62 have a mechanical fuze setter to automatically set MT/PD and CVT-RF fuzes and an inductive setter to automatically set ET and MFF fuzes, the 76mm does not have either. Accuracy of both guns degrades with range. Therefore, effectiveness against small or point tar-gets decreases with range. Open fire range on an incoming target should take into account the type of fuze/round loaded in the mount, number of rounds in the drum, rate of fire, and the time of intercept. Generally, for any fast moving threat, open fire should start around 10,000 yards even if the radars have locked on earlier. This will insure

that there are still rounds in the mount being fired at the threat when the gun reaches its peak effec-tiveness. The probability of a hit does not become significant until the target is near minimum range where the cumulative probability reaches near 100% for most targets.

2-5.1.3. Ship/Small Boat Targets. The round of choice for use against ship/small boat targets is determined by the size, maneuverability, range and desired effect on the target. Most frigate-size or larger ships (if engaged with a gun) should be engaged using the delay mode of PD/DLY fuzed projectiles for structural damage or ET, RF and MFF fuzed projectiles for topside damage. Patrol craft and small boats should be engaged using ET, CVT-RF, VT-RF or MFF fuzed projectiles. High speed maneuvering surface targets (HSMST) should be engaged using ET, CVT-RF, VT-RF or MFF fuzed projectiles in order to produce a pattern of fragmentation in the vicinity of the target. The ET fuze will trigger at the set time of target inter-cept determined by the GWS. The CVT-RF fuzes will not detect small craft, but will trigger on the water surface at approximately 30 feet above the surface. The VT-RF fuzes will most likely detect the small craft, if not, they will trigger on the water surface, but at a lower, less effective HOB than CVT rounds for close-in targets. The MFF fuzes will most likely detect the small craft in the prox-imity mode, if not, they will trigger on the water surface. They can also be set in the electronic time mode to trigger at the target intercept time. The ET fuze is the first fuze of choice for HSMSTs fol-lowed by the MFF, CVT-RF and VT-RF, respec-tively. The infrared signature of most ships and small boats is insufficient to cause the VT-IR pro-jectiles to function in proximity mode. Use MT/PD, PD/DLY and IR fuzes as a last resort.

2-5.1.4. Aircraft/Missile Targets. The VT-IR is the fuze of choice for use against “hot” infrared air targets (jets and missiles). Piston engine air-craft can activate the IR fuze, but the energy con-tent is so small that the bullet must be placed closer than normal to the target. MFF and VT-RF fuzed projectiles are the recommended first and second choices respectively against all “cold” targets and are close second choices for use against all “hot” air targets. The MFF and VT-RF fuzes can be used

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to engage all air targets with a range of radar cross sections at all altitudes. However, VT-RF fuzes capability is somewhat degraded when engaging low altitude and relatively small radar cross section air targets. Meaning that the bullet must be placed slightly closer to these targets. The MFF fuze is much less susceptible to these conditions as it has better sensitivity and clutter filtering capabilities, making it the best choice. The ET and MT fuzes may be used to engage slow-moving air targets mainly for harassment or warning shots, but are not very effective. CVT-RF fuzed projectiles are not very effective either against air targets. The CVTs were designed for shore bombardment, but they are a step above a PD fuze as they can detect an air tar-get from a couple of feet away.

2-5.1.5. Surface Target Application. Proxim-ity-fuzed projectiles which burst above the surface are significantly more effective against soft surface targets than ground impact bursts. CVT-RF and MFF fuzed projectiles are the recommended first and second choices for use against surface targets, such as light materiel, radar, personnel, and ship topside equipment. The fragments of an exploding projectile can do tremendous damage to these tar-

gets. CVT-RF and MFF fuzed projectiles have the advantage that they may be fired over friendly troops or high obstacles without danger of the fuze early functioning. VT-RF fuzed projectiles are the recommended third choice for use against soft sur-face targets. These fuzes are equally as effective as the CVT-RF and MFF fuzes, but do not have the delay turn-on or as reliable a height of burst. If a ship were actively engaged in a shore bombard-ment role and there were good reason to expect air targets to suddenly appear, it would be a good pre-caution to have MFF or VT-RF fuzed projectiles in the hoist and use them in the shore bombardment role. VT-IR fuzes are not recommended for use in a surface target role they will only act as a PD round. MT/PD fuze can be used, but only 10 per-cent of the rounds will be effective airbursts at long ranges with close to 50 percent being PD. ET fuze, though not as effective as the proximity fuze, can be used but it is not recommended at long ranges as it does not contain a PD backup. When hard area targets are being shelled such as heavily armored vehicles, an urban area or a fortified shore position, PD/DLY fuzed rounds are the first choice when used in the delay mode.

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CHAPTER 3

AMMUNITION ASSEMBLIES

3-1. INTRODUCTION

3-1.1. General. Ammunition assemblies for Navy guns 20mm and larger in the current inven-tory for the surface Navy 2T cog are described in this chapter. This chapter covers the general char-acteristics, specific data, interface, identification, precautions in handling and use, and information for packing and shipping for the complete round. Illustrations showing component parts are given for each different type projectile. The ammunition assemblies are arranged in an ascending order according to gun size.

3-1.2. Cartridge or Projectile Load Identifica-tion. Abbreviations used for cartridge or round designations are the following:

3-2. 20 MILLIMETER AMMUNITION

3-2.1. General. The present 20 millimeter (20mm) guns M61A1 and MK 16 are automatic guns, used against air and surface targets. The 20mm ammunition used by the surface Navy may be requisitioned in belted configuration only and is issued in the form of fixed, completely assembled rounds, referred to as cartridges. The shape, length, weight, and ballistics of these cartridges vary slightly.

Currently, there are cartridges from three series of 20mm ammunition in the surface Navy stock – the M50, M90, and M200 series. Cartridge types are identified and issued as follows:

3-2.2. Ammunition/Interface.

3-2.2.1. M50 Series. M50 series 20mm ammu-nition described in this section is fired in an M61A1 six-barrel, electrically fired, automatic gun. It uses an ammunition feeder that handles the MK 7 loading links to fire 6,000 to 7,200 rounds per minute.

3-2.2.2. M90 and M200 Series. Both of these series of ammunition are fired in a MK 16 percus-sion fired machine gun. The MK 16 machine gun is an air-cooled weapon that fires from 650 to 800 rounds of ammunition per minute. Ammunition is fed into the gun from a feed mechanism that pres-ents the rounds in a disintegrating link belt.

3-2.3. Ammunition Characteristics. The 20mm ammunition comprises the primer, the pro-pellant, the cartridge case, and the projectile assembled into a single unit called a cartridge. This may be loaded into the gun in a single opera-tion. The characteristics of 20mm ammunition have been grouped according to the three series.

3-2.3.1. M50 Series Ammunition. M50 con-figuration ammunition for the M61A1 Navy gun is issued in the form of cartridges. All service car-tridges have matched ballistics and are electrically primed. Initially procured ammunition is not graded, and all acceptable lots are serviceable for issue and use in applicable weapons.

3-2.3.1.1. Projectile.

3-2.3.1.1.1. Target Practice (TP) (M55A2). This projectile is used for target practice and has no explosive filler. The shape and ballistic properties

CARTRIDGE TYPE DODIC

Target practice, TP – M99/M204 A777Target practice, TP – M55A2 A661High explosive, Incendiary, HEI – M210

A785

Incendiary, INC – M96 A776Armor-piercing, AP-T – M95 tracer A765Armor-piercing, discarding sabot, AP-DS – MK 149 MOD 0

A675

Armor-piercing, discarding sabot, AP-DS – MK 149 MOD 2

A676

Armor-Piercing, Discarding Sabot, AP-DS – MK 149 MOD 4

A692

Armor-Piercing, Discarding Sabot, AP-DS – MK 149 MOD 5

A763

Armor-Piercing, Discarding Sabot, AP-DS-MK 244 MOD 0

AA61

Dummy - M51A4N AA20


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are similar to those of the other M50 series configuration ammunition. The projectile has a steel body with a solid aluminum nose piece swaged into a cavity in the forward end.

3-2.3.1.1.2. MK 68 Armor-Piercing, Discard-ing Sabot (AP-DS). This projectile is an inert, subcaliber projectile (Figure 3-1). The projectile consists of a depleted uranium (Mods 0, 1, 2) or tungsten (Mods 4, 5) penetrator surrounded by a discarding sabot and an aluminum pusher plug assembly. The pusher plug has a nylon rotating band swaged into a circumferential groove near its aft end. The assembly (MK 149 cartridge) and the M61A1 gun (MK 15 Phalanx Weapon System) are equipped with a linkless ammunition handling sys-tem and serves as a close-in weapons system (CIWS). The ammunition is electrically primed and is belted in MK 7 loading links (Figure 3-2) for loading into the M61A1 gun. The MK 149 car-tridges are supplied in 100-round belts in M548 metal ammunition containers. A summary of the M50 series characteristics is given in Table 3-1.

3-2.3.1.1.3. Enhanced Lethality Cartridge (ELC), Armor-Piercing Discarding Sabot (AP-DS) (MK 244 MOD 0). This projectile is an inert, subcaliber projectile. See Figure 3-3. The projectile consists of a tungsten penetrator sur-rounded by a discarding sabot and an aluminum pusher plug assembly. The discarding sabot and the rotating band consist of a single component molding of glass reinforced polyetherimide. This material fills the circumferential groove near the aft end of the pusher plug and surrounds the entire exposed portion of the projectile assembly. The assembly (MK 244 Cartridge) and the M61A1 gun (MK 15 Phalanx Weapon System) are equipped with a linkless ammunition handling system and serves as a close-in weapons system (CIWS). The ammunition is electrically primed and is belted in MK 7 loading links for loading into the M61A1 gun. The MK 244 cartridges are supplied in 100-round belts in M548 metal ammunition contain-ers. A summary of the M50 series characteristics is given in Table 3-1.Figure 3-1 20 Millimeter Armor-Piercing,

Discarding Sabot Projectile, MK 68

Figure 3-2 20 Millimeter MK 7 Loading Links

Figure 3-3 20 Millimeter Enhanced Lethality Cartridge, Armor-Piercing, Discarding Sabot Projectile

SW030-AA-MMO-010

3-3

3-2.3.1.1.4. Dummy Round (M51A4N). The dummy round consists of a steel core surrounded by fiberglass reinforced nylon and is completely inert. This cartridge is belted into MK 7 loading links and is used in the MK 15 Phalanx Weapon System. The dummy is used for loading/down-loading exercised, dry cycling of weapons for maintenance, weapon checkout and training. The dummy is identical to the MK 149 and MK 244 ammunition in length and exterior profile and iden-tical to the MK 149 ammunition in weight and cen-ter of gravity location.

3-2.3.1.2. Propelling Charge. The M50 series cartridge may be assembled with either the M103 brass case or the M103A1 steel case. To ignite the propellant charge, the base of the case is fitted with M52A3B1 electric primer (see Chapter 5) that is activated by the passage of an electric current to the primer by the gun firing pin. The electric

primer is used in all current M50 series service car-tridges and consists of an open-ended brass cup containing a brass button insulated from the cup by a plastic liner. The firing pin of the gun contacts this button. In contact with the other side of the button is the ignition charge consisting of a con-ductive explosive mixture. This is retained by a paper disc and a metal support cup. The electri-cally initiated primer ignites the propellant charge. The primer explosive element is designed to with-stand the shock received in normal handling. However, it is sensitive to electromagnetic and electrostatic energy, and care should be exercised to prevent the primer button from coming in con-tact with electrical wiring, static charge buildup on the human body, or other sources of electricity. The primer electric resistance is 1,000 ohms mini-mum and 1,200,000 ohms maximum. The electri-cal sensitivity for 100 percent ignition is 160 Vdc.

Table 3-1 M50 Series Ammunition Data

Projectile Propelling Charge

Total Weight (g) (Approx.)

Cartridge Assembly DODIC Type

Fuze

Explosive Filler Propellant Filler

Primer CartridgeCase

Type Wt. (lb.) Type Wt. (g)

MK 149 MOD 0 A675 AP-DSMK 68 Mods

0, 1

None None – WS 19781 42.12(nominal)

M52A3B1 M103 Brass

256.93

MK 149 MOD 2 A676 AP-DS MK 68 MOD 2


M52A3B1 M103 Brass

256.93

MK 149 MOD 4 A692 AP-DS MK 68 MOD 4


M52A3B1 M103 Brass

256.93

MK 149 MOD 5 A763 AP-DSMK 68 MOD 5


M52A3B1 M103 Brass

256.93

M51A4N AA20 Dummy None None – None – None None 257.6

M55A2 A661 TP None None – MIL-P-3984

38.23 M52A3B1 M103 Brass orM103A1

Steel

254.99

MK 244 MOD 0 AA61 AP-DS None None - OBP 888 54.00 (nominal)

M52A3B1 M103 Brass

307.99

SW030-AA-MMO-010

3-4

3-2.3.2. M90 Series Ammunition.

THE 20MM M90 AMMUNITION IS PERCUSSION PRIMED. AVOID STRIKING THE PRIMER AGAINST ANY OBJECT.

WHEN THE M90 SERIES AMMUNI-TION BELT IS FED INTO THE FEED MECHANISM, THE CLOSED SIDE OF THE LINKS MUST BE UP (ON TOP).

There are three service cartridges and one practice cartridge available in the M90 series ammunition for the MK 16 gun. Data on these car-tridges are given in Table 3-2. This ammunition is percussion-primed and is belt-fed into the gun by M8 or M10 disintegrating links (Figure 3-4). All of M90 series projectiles have matched ballistics at 100 yards with a muzzle velocity of 2,730 feet per second. The length, weight, and ballistics of these cartridges are approximately the same. The M90 ammunition is supplied in quantities of 120 rounds in a metal-lined wooden box, or 165/180 rounds in a metal MK 1 small arms ammunition container. The belted ammunition is currently produced for a left-hand feeding mechanism. The feed procedure for the MK 16 system with the belted M8 or M10 disintegrating links is given in the following subor-dinate paragraphs.

3-2.3.2.1. Feed Procedure for Belted Ammuni-tion.

3-2.3.2.1.1. General. The feed mechanism brings either right- or left-hand belted ammunition from an ammunition box through a feed chute and into the feeder where it separates the cartridge from the links and feeds the cartridges one at a time into the gun.

3-2.3.2.1.2. Right-Hand Feed. Right-hand belted ammunition is fed into the right-hand feed mechanism, empty single loop first, with trailing

double loop loaded, to prevent snagging the feed chute. Left-hand belted ammunition is fed into the right-hand feed mechanism, loaded double loop first, with the trailing empty single loop cut off or bent closed, to prevent snagging the feed chute.

3-2.3.2.1.3. Left-Hand Feed. Left-hand belted ammunition is fed into the left-hand feed mechanism, empty single loop first, with trailing double loop loaded, to prevent snagging the feed chute. Right-hand belted ammunition is fed into the left-hand feed mechanism, loaded double loop first, with the trailing empty single loop cut off or bent closed, to prevent snagging the feed chute.

3-2.3.2.2. Projectiles.

3-2.3.2.2.1. Armor-Piercing, Tracer (AP-T) (M95). The AP-T cartridge (Figure 3-5) is a stan-dard round for use against armored targets. The projectile is a hardened, solid shot made from bar or forged steel. A drawn steel (hollow) windshield is crimped into annular grooves in the projectile body. The portion of the windshield over the crimping acts as the bourrelet of the projectile. The base of the projectile contains a red tracer sealed in by means of a metal closing cup. Maxi-mum tracer burning time is approximately 2.25 seconds, which is equivalent to a range of approxi-mately 1,400 yards. Minimum burning time is approximately 2.0 seconds, which is equivalent to a range of 1,270 yards.

Figure 3-4 M8 and M10 Disintegrating Links for 20 Millimeter M90 and M200 Series

SW030-AA-MMO-010

3-5

3-2.3.2.2.2. Incendiary (INC) (M96). The INC cartridge (Figure 3-6) is used against light material targets and functions with an incendiary effect. The projectile body is made of cold-drawn steel. A die-cast zinc nose cap is threaded into the projectile body. Both the body and nose are filled with an incendiary material. This round does not require a fuze, as functioning is initiated by impact of the nose on the target.

3-2.3.2.2.3. Target Practice (TP) (M99). The TP cartridge is used for practice firing. The projec-tile is similar in shape and ballistic properties to the incendiary cartridge (M96) but is hollow and con-tains no explosive. The nose consists of a zinc die casting as in the M96 incendiary, but its weight is adjusted to give the projectile a weight of 131.6 grams. The projectile body is made of cold-drawn steel.

3-2.3.2.3. Propelling Charge. The propelling charges (Figure 3-7) used with the M90 and the M200 series ammunition are identical. The

M21A1 cartridge case is made of brass and weighs approximately 97.2 grams. The M36A1 percus-sion primer contains a 0.136-gram charge of primer mixture while the cartridge case is loaded with approximately 31.8 grams of single-base (nitrocel-lulose) propellant. The cartridge case is attached rigidly to the projectile by means of a 360 degree crimp.

3-2.3.3. M200 Series Ammunition.

THE 20MM M200 SERIES AMMU-NITION IS PERCUSSION-PRIMED. AVOID STRIKING THE PRIMER AGAINST ANY OBJECT.

The M200 series ammunition interfaces with the 20mm MK 16 machine gun. The M204 (TP) and M210 (HEI) cartridges are the only cartridges in this series of 20mm ammunition. A data sum-

Table 3-2 M90 Series Ammunition Data (Maximum Length - 7.23 Inches)

Projectile Propelling Charge Total Weight

(g) (Approx.)

Cartridge Assembly DODIC Type Wt. (g) Fuze

Explosive Filler Propellant FillerPrimer Cartridge

CaseType Wt. (g) Type Wt. (g)

M95 A765 AP-T 131.54 None None None FNH,IMR-4879

31.75 M36A1(MK 31)

M21A1Brass

258.55

M96 A776 INC 122.47 None INC 9.07 FNH,IMR-4879

31.75 M36A1(MK 31)

M21A1Brass

249.48

M99 A777 TP 131.54 None None None FNH,IMR-4879

31.75 M36A1(MK 31)

M21A1Brass

258.55

Figure 3-5 20 Millimeter Armor-Piercing, Tracer (M95) Projectile

Figure 3-6 20 Millimeter Incendiary (M96) Projectile

SW030-AA-MMO-010

3-6

mary for the M200 series is given in Table 3-3. The M204 and M210 cartridges are percussion primed and are belt-fed by M8 or M10 disintegrat-ing links (Figure 3-4). The belted ammunition can be requisitioned in either right- or left-hand feed (see paragraph 3-2.3.2.1.), as required by the gun feed mechanism, and is packed with 150 cartridges per M548 container. The cartridges are also avail-able in bulk form in quantities of either 150 or 200 rounds in the M548 container. The major differ-ence between the M200 series M210 HEI cartridge and the M90 series obsolete and unsafe M97 HEI cartridge is that the M210 cartridge is fitted with the boresafe M505 point detonating fuze. The M204 (TP) cartridge is interchangeable with the M99 (TP) cartridge.

3-2.3.3.1. Projectiles.

3-2.3.3.1.1. Target Practice (TP) (M204). This cartridge is used for practice firings. The projectile body is hollow and contains no explosive. The

nose piece is made of solid aluminum. The projec-tile (M99A1) used in the M200 series ammunition is considered an improved design.

3-2.3.3.1.2. High Explosive Incendiary (HEI) (M210). This cartridge (Figure 3-8) is used against light material targets and functions with both explosive and incendiary effect. The high explo-sive is tetryl and is located in the nose portion of the projectile; the incendiary mixture is located in the base. The combined weight of the high explo-sive/incendiary filler is 7.71 grams composed of 2.27 grams of incendiary moisture and 5.44 grams of tetryl. Upon impact, the M505A3 fuze func-tions; the filler detonates; the shell shatters; and the incendiary composition ignites. The thickness of the base is approximately 0.2 inch, and a base cover is welded on for additional protection.

Figure 3-7 20 Millimeter Propelling Charge

Table 3-3 M200 Series Ammunition Data (Maximum Length - 7.25 Inches)


(g) (Approx.)

Cartridge Assembly DODIC Type Fuze

Explosive Filler PropellantPrimer Cartridge


M204 A777 TP - - 5.44 FNH, IMR-7013

31.75 M36A1E1 M21A1 Brass

259.201

M210 A785 HEI PD, M505A3

Tetryl

INC

5.44

2.27

FNH, IMR-7018

31.75 M36A1E1 M21A1 Brass

259.201

1 - Nominal Weight

SW030-AA-MMO-010

3-7

3-2.3.3.2. Propelling Charge. The propelling charge (Figure 3-7) used with the M90 and the M200 series ammunition are identical. See para-graph 3-2.3.2.3. The M204 cartridge can be loaded with an alternate (WC 875) propellant.

3-2.4. Packing. The ammunition is handled and shipped according to OP 4 and OP 5. The ammu-nition and container are painted, marked, and let-tered in accordance with WS 18782. The following bulk packing requirements apply:

3-2.5. Ballistic Data. The ballistic data for these cartridges are listed as follows:

3-2.5.1. Average Muzzle Velocity.

3-2.5.1.1. M50 Series. AP-DS (MK 149) – 3,685 feet per second AP-DS (MK 244) - 3610 feet per second

3-2.5.1.2. M90 Series.AP-T (M95) – 2,730 feet per secondINC (M96) – 2,760 feet per second

TP (M99) – 2,730 feet per second

3-2.5.1.3. M200 Series.TP (M204) – 2,730 feet per second

HEI (M210) – 2,730 feet per second

3-2.5.2. Maximum Range.

3-2.5.2.1. M50 Series. MK 149 – 11,750 yards MK 244 - 10,100 yards

3-2.5.2.2. M90 Series. AP-T (M95) – 5,900 yards INC (M96) – 5,700 yards TP (M99) – 5,750 yards

3-2.5.2.3. M200 Series. TP (M204) – 5,750 yards HEI (M210) – 5,750 yards

Figure 3-8 20 Millimeter High Explosive Incendiary (M210) Projectile

NALC TYPE REQUIREMENTS

A675 MK 149 MOD 0 MIL-STD-1323/187

A676 MK 149 MOD 2 MIL-STD-1323/187

A692 MK 149 MOD 4 MIL-STD-1323/187

A763 MK 149 MOD 5 MIL-STD-1323/187

A765 M95

A776 M96

A777 M99/M204

A785 M210

AA61 MK 244 MOD 0 MIL-STD-1323/187

AA20 Dummy MIL-STD-1323/187

SW030-AA-MMO-010

3-8


THE 25MM CARTRIDGES ARE PERCUSSION PRIMED. AVOID STRIKING THE PRIMER AGAINST ANY OBJECT.

3-3.1. General. The 25mm MK 38 Gun Weap-ons System (GWS) is a deck-mounted, hand-trained, and elevated weapon deployed on Navy and Coast Guard ships and patrol boats. The MK 38 GWS uses the M242 25mm gun (also known as the chain gun). The M242 is externally powered, single-barreled, belt-fed, air-cooled, and capable of fully automatic fire at 200 rounds per minute. The MK 38 is employed primarily against surface targets. The 25mm ammunition used in the MK 38 GWS is usually issued belted and all rounds are fixed. Cartridge types are identified as follows:

3-3.2. Ammunition Interface. The 25mm ammunition is used in the M242 automatic gun. The M242 gun has a feeder that accepts 25mm rounds belted in the M28 firing link. Spent car-tridge cases and links are ejected from the M242 gun during firing.

3-3.3. Ammunition Characteristics. Each 25mm live round consists of the percussion primer with booster pellet, the propellant, the cartridge case, and the projectile. These components are assembled into a fixed unit identified as a car-tridge. Initially procured live rounds are not graded

and all acceptable lots are approved for use in any serviceable MK 38 GWS. The 25mm dummy round has no live components (no primer or pro-pellant) and is inert. Table 3-4 presents 25mm individual round-type characteristics.

3-3.3.1. Projectiles.

3-3.3.1.1. Armor-Piercing, Discarding Sabot, Tracer (AP-DS-T) (M791). This projectile (Fig-ure 3-9) is designed for use against lightly armored targets. The projectile consists of a solid tungsten alloy penetrator (subprojectile), a pressed-on alu-minum windshield, pressed-in tracer pellets, a molded discarding-type nylon sabot, a staked alu-minum base with rotating band, and a pressed-on polyethylene nose cap. Upon exit of this projectile from the gun muzzle, all parts fall rapidly away from and behind the penetrator, which continues in stabilized flight to the target. This projectile has the highest muzzle velocity, flattest trajectory, and shortest time of flight to the target in the 25mm ammunition family.

3-3.3.1.2. Target Practice, Tracer (TP-T) (M793). This projectile (Figure 3-10) is used for training purposes and in combat against personnel and unarmored targets. The hollow projectile body is made of C1035 steel with a screwed on steel nosepiece, a swagged rotating band, and tracer pel-lets pressed in the projectile base. The TP-T pro-jectile duplicates the HEI-T projectile in exterior ballistic performance and is identical to the HEI-T in size and weight. See Figure 3-11.


Armor-Piercing, Discarding Sabot, Tracer

AP-DS-T – M791 A974

Target Practice, Tracer TP-T – M793 A976

High Explosive, Incendiary Tracer

HEI-T – MK 210 A981

Semi-Armor- Piercing, High Explosive, Incendiary, Tracer

SAP-HEIT – PGU-32/U A991

Dummy Dummy – M794 A967

Figure 3-9 25 Millimeter Armor-Piercing, Discarding Sabot Tracer Projectile (M791)

SW030-AA-MMO-010

3-9

3-3.3.1.3. High Explosive, Incendiary, Tracer (HEI-T) (MK 210). This projectile (Figure 3-11) is used to engage unarmored targets. The projectile consists of a hollow steel body, a screwed on M505A3 fuze, a swagged iron rotating band, various explosive mixes depending on the projectile Mod (see Table 3-4), and tracer pellets pressed into the projectile base. The HEI-T projectile detonates upon target impact, spraying the target with fragments and starting fires among combustible target materials. The HEI-T projectile is the most widely used round in combat operations.

Figure 3-10 25 Millimeter Target Practice, Tracer Projectile (M793)

Figure 3-11 25 Millimeter High Explosive Incendiary Projectile MK 210 Figure 3-12 25 Millimeter Semi-Armor-

Piercing High Explosive Incendiary Projectile (PGU-32/U)

Table 3-4 25 Millimeter Ammunition Data


(g) (Approx.)

Cartridge Assembly DODIC Type Wt. (g) Fuze

Explosive Filler Propellant FillerPrimer Cartridge


M794 A967 Dummy - None - - None - None - 501.0

M791 A974 AP-DS-T 134.0 None - - RadfordAP 25

98Approx

.

M115w/booster

Steel12013217

458.0

M793 A976 TP-T 117.0Approx.

None - - OlinWC-890

M115w/booster

Steel12013217

501.0

MK 210 MOD 0

A981 HEI-T 183.5Approx.

PDM505A3

H761 28.5 BallPowder

M115w/booster

Steel12013217

501.0

MOD 1 PDM505A3

PBXN-5 &Aluminum

25.0 or 95Approx

.

M115w/booster

Steel12013217

501.0

MOD 2 PDM505A3

PBXN-5 &Zirconium

17.22.7

HerculesHC-36FS

M115w/booster

Steel12013217

501.0

PGU-32/U AA98 SAP-HEIT

183.5Approx.

None PBXN-5 &Zirconium

12.01.4

Extruded M115w/booster

Steel12013217

501.0

SW030-AA-MMO-010

3-10

3-3.3.1.4. Semi-Armor-Piercing High Explo-sive, Incendiary, Tracer (SAP-HEIT) (PGU-32/U). This projectile (Figure 3-12) is a multipurpose projectile designed for use against lightly armored and unarmored targets. It consists of a hardened steel body that acts like a penetrator, a rotating band, a high explosive filler, an incendiary mix-ture, a nose containing incendiary mixes that acts as a pyrotechnic fuze, and tracer pellets in the pro-jectile base. Upon target impact frictional heating initiates the pyrotechnic fuze, which detonates the warhead, spraying the target with fragments and starting fires among combustible materials. The armor-piercing element of the projectile continues to penetrate and damage the target. The multipur-pose projectile thus performs several functions: high explosive warhead, armor penetrator, and fire-starter. This projectile has replaced armor-piercing and high explosive rounds during some combat engagements, thereby simplifying the logistics of combat unit resupply.

3-3.3.1.5. Dummy Round (M794). The dummy round is made of steel, is completely inert, and is used for demonstration and display purposes and during gun system loading/downloading exercises and dry cycling of the weapon for maintenance, weapon checkout, or gun crew training drills. The dummy is identical to HEI-T and TP-T ammuni-tion in length, exterior profile, weight, and center of gravity location.

3-3.3.2. Propelling Charge. The 25mm service rounds are assembled using the steel cartridge case, drawing no. 12013217. To ignite the propelling charge within the cartridge case, the base of the case contains the M115 percussion primer and booster pellet. This primer is actuated (fired) when struck by the firing pin in the M242 gun. The M115 primer consists of an anvil, a body, and percussion priming mix. When the gun firing pin strikes the primer face, the face collapses against the primer anvil, pinching a small quantity of the priming mix between the primer face anvil. This pinching pres-sure raises the temperature of priming mix to the

ignition point. The mix ignites and the resulting flame shoots through a hole in the primer body and ignites the booster pellet. Flame from the mix and pellet passes through a hole in the primer pocket in the cartridge case base and into the propellant chamber within the cartridge case. This ignites the main propelling charge (propellant). The propel-lant burns very rapidly, generating high pressure within the cartridge case and forcing the projectile out of the case mouth and down and out the gun barrel.

3-3.3.3. M28 Ammunition Link. All 25mm service rounds fired in the M242 gun are belted in the steel 2-piece M28 link. This link is a side-strip-ping, disintegrating belt-type. Rounds of ammuni-tion are stripped from the side of the M28 link by the feeder on the M242 gun. The link belt comes apart into individual links when rounds are stripped from the links.

3-3.4. Packing. All 25mm cartridges are linked into belts of 55 rounds using the M28 link. Each belt is packed into the CNU-405/E ammunition container as specified in Drawing 53711-5167214. Twenty CNU-405/E ammunition containers are banded to the MK 3 MOD 0 pallet to form the unit pack as specified in Drawing 53711-6214102.

3-3.5. Ballistic Data. Ballistic data for the 25mm service rounds are as follows:

3-3.5.1. Average Muzzle Velocity.AP-DS-T 4,370 feet per secondTP-T 3,610 feet per secondHEI-T 3,610 feet per secondSAP-HEIT 3,610 feet per second

3-3.5.2. Maximum Range.AP-DS-T 16,400 yards

TP-T 6,500 yards HEI-T 6,500 yards SAP-HEIT 6,500 yards

SW030-AA-MMO-010

3-11



3-4.1. General. The 30mm MK 46 Gun Weap-ons System (GWS) is a fully stabilized weapon deployed on the Marine Corps Expeditionary Fighting Vehicle and on Navy ships including the LPD-17 San Antonio class of amphibious trans-port dock ships. The Naval configuration utilizes a barbette-mounted GWS capable of either remote or local operation. The MK 46 GWS uses the MK 44 Enhanced Bushmaster II gun capable of firing either 30mm GAU-8 or Super 40 ammunition. The MK 44 is an externally powered, single-barreled, air-cooled, open bolt, dual-feed chain-operated machine gun capable of fully automatic fire at 200 rounds per minute. The 30mm ammunition used in the MK 46 GWS is issued belted and all rounds are fixed. Cartridge types are identified in Table 3-5.

3-4.2. Ammunition Interface. The 30mm ammunition is used in the MK 44 automatic gun. The MK 44 gun has a dual-feed that accepts 30mm rounds belted in the MK 15 firing link. Spent car-tridge cases and links are ejected from the MK 44 gun during firing.

3-4.3. Ammunition Characteristics. Each 30mm live round consists of the percussion primer, the flash tube with booster pellet, the propellant, the cartridge case, and the projectile. These compo-nents are assembled into a fixed unit identified as a cartridge. Initially procured ammunition is not graded, and all acceptable lots are serviceable for issue and use in applicable weapons. The 30mm dummy round has no live components (no primer or propellant) and is inert. Table 3-6 presents 30mm individual round-type characteristics.

3-4.3.1. Projectiles.

3-4.3.1.1. Armor-Piercing, Fin-Stabilized, Discarding Sabot, Traced (APFSDS-T) (MK 258 or MK 268). This projectile (Figures 3-13 and 3-14) is a multipurpose projectile designed for use against lightly armored targets. The projectile con-sists of a high-density tungsten alloy fin-stabilized long rod penetrator (subprojectile), pressed-in tracer pellets, a plastic or aluminum three petal sabot, a glass reinforced nylon rotating band, and a windscreen. Upon exit of this projectile from the gun muzzle, all parts fall rapidly away from and behind the penetrator, which continues in stabilized flight to the target. This projectile has the highest muzzle velocity, flattest trajectory, and shortest time of flight to the target in the 30mm ammunition family.

Table 3-5 30 Millimeter Ammunition for MK 46 Gun Weapons System

CARTRIDGES TYPE DODIC

Armor-Piercing, Fin Stabilized, Discarding Sabot, Traced APFSDS-T MK 258 or MK 268

AA71 or AA72

High Explosive, Incendiary Traced and Multi-Purpose Low Drag Traced Linked in 1 to 1 Ratio

HEI-T/MPLD-T MK266/MK264

AA89

Target Practice, Traced TP-T MK 239

AA90

Dummy Dummy - PGU 16/A B099

SW030-AA-MMO-010

3-12

Table 3-6 30 Millimeter Ammunition DataProjectile Propelling Charge Total

Weight (g)

(Approx.)

Cartridge Assembly DODIC Type Wt.

(g) FuzeExplosive Filler Propellant Filler

Primer CartridgeCaseType Wt.

(g) Type Wt. (g)

MK 258 AA71 APFSDS-T 230 None None - Extruded, Double Base

171 DNAG 8235 Steel 710

MK 268 AA72 APFSDS-T 235 None None - Extruded, Double Base

179 DNAG 8235 Steel 725

MK 266

AA89

HEI-T 362Pd, Low

Drag Proprietary

PBXN-5 &

Zirconium53 Extruded,

Single Base 153 M36A2 Steel or Aluminum 670

MK 264 MPLD-T 343 NonePBXN-5

& Zirconium

29 Extruded, Double Base 157 DNAG

8235 Steel 830

MK 239 AA90 TP-T 372 None None -- Extruded, Single Base

153 M36A2 Aluminum 675

PGU 16/A B099 TP 378 None None Extruded, Single Base

145 M36A2 Aluminum 681

Figure 3-13 30 Millimeter Armor-Piercing, Fin-Stabilized, Discarding Sabot, Traced (APFSDS-T) (MK 258)

Figure 3-14 30 Millimeter Armor-Piercing, Fin-Stabilized, Discarding Sabot, Traced (APFSDS-T) (MK 268)

SW030-AA-MMO-010

3-13

3

3-4.3.1.2. High Explosive, Incendiary, Traced (HEI-T) (MK 266). This projectile (Figure 3-15) is used in conjunction with the MPLD-T (MK 264) projectile in a cartridge configuration linked in a one to one ratio. This configuration is used to combat personnel and light to medium material tar-gets. This projectile adds a tracer and a lower drag fuze as a modification to the Air Force 30mm PGU-13 HEI untraced projectile. The projectile consists of a hollow steel body, a screwed on point detonating, low drag fuze, a glass reinforced nylon rotating band, an explosive mix consisting of PBXN-5 high explosive and a zirconium based incendiary, and tracer pellets pressed into the pro-jectile base. The HEI-T projectile detonates upon target impact, spraying the target with fragments and starting fires among combustible target materi-als.

3-4.3.1.3. Multi-Purpose, Low Drag, Traced (MPLD-T) (MK 264). This projectile (Figure 3-16) is used in conjunction with the HEI-T (MK 266) projectile in a cartridge configuration

linked in a one to one ratio. This configuration is used to combat personnel and light to medium material targets. The projectile consists of a hol-low, hardened steel body that acts like a penetrator, a glass reinforced polyetherimide rotating band, a PBXN-5 high explosive filler, a zirconium based incendiary mixture, a nose containing incendiary mixes that acts as a pyrotechnic fuze, and tracer pellets in the projectile base. Upon target impact, frictional heating initiates the pyrotechnic fuze, which detonates the warhead, spraying the target with fragments and starting fires among combusti-ble materials. This projectile may also contain an optional self-destructing explosive load. The armor-piercing element of the projectile continues to penetrate and damage the target. The multipur-pose projectile thus performs several functions: high explosive warhead, armor penetrator, and fire-starter.

Figure 3-15 30 Millimeter High Explosive, Incendiary, Traced (HEI-T) (MK 266)

Figure 3-16 30 Millimeter Multi-Purpose, Low Drag, Traced (MPLD-T) (MK 264)

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3-4.3.1.4. Target Practice, Traced (TP-T) (MK 239). This projectile (Figure 3-17) is used for training purposes and in combat against personnel and unarmored targets. This projectile adds a tracer as a modification to the Air Force 30mm PGU-15 TP untraced projectile. The solid projectile body is made of 1030 CD or equivalent steel with a swaged on alumi-num nosepiece, a glass reinforced nylon rotating band, and tracer pellets pressed in the projectile base. The TP-T projectile duplicates the HEI-T projectile in exte-rior ballistic performance and is identical to the HEI-T in size and weight.

3-4.3.1.5. Dummy Round (PGU 16/A). The dummy round is made of steel, is completely inert, and is used for demonstration and display purposes and during gun system loading/downloading exercises and dry cycling of the weapon for maintenance, weapon checkout, or gun crew training drills. The dummy is identical to HEI-T and TP-T ammunition in length, exterior profile, weight, and center of gravity location.

3-4.3.2. Propelling Charge. The 30mm service rounds are assembled using either a steel or aluminum cartridge case depending on configuration. The car-tridge case is attached rigidly to the projectile by means of a 360 degree crimp. To ignite the propelling charge within the cartridge case, the base of the case contains a percussion primer and flash tube. This primer is actu-ated (fired) when struck by the firing pin in the MK 44 gun. The primer consists of an anvil, a body, and per-cussion priming mix. When the gun firing pin strikes the primer face, the face collapses against the primer anvil, pinching a small quantity of the priming mix between the primer face and anvil. This pinching pres-sure raises the temperature of the priming mix to the ignition point. The mix ignites and the resulting flame passes through a hole in the primer pocket of the car-

tridge case base and into the flash tube igniting the booster pellets. Flame from the pellets ignite the main propelling charge (propellant). The propellant burns very rapidly, generating high pressure within the car-tridge case and forcing the projectile out of the case mouth and down and out the gun barrel.

3-4.3.3. MK 15 Ammunition Link. All 30mm service rounds fired in the MK 44 gun are belted in the steel MK 15 link. This link is a side-stripping, disinte-grating belt-type. Rounds of ammunition are stripped from the side of the MK 15 link by the feeder on the MK 44 gun. The link belt comes apart into individual links when rounds are stripped from the links.

3-4.4. Packing. All 30mm cartridges are linked into belts of 15 rounds using the MK 15 link. Two belts of ammunition (30 cartridges) are packed into the M592 ammunition can. Twenty M592 ammunition cans, banded to the MK 3 MOD 0 pallet, form the unit load.

3-4.5. Ballistic Data. Ballistic data for the 30mm service rounds are as follows:

3-4.5.1. Average Muzzle Velocity.APFSDS-T (MK 258) 4,692 feet per secondAPFSDS-T (MK 268) 4,610 feet per secondHEI-T 3,540 feet per secondMPLD-T 3,511 feet per secondTP-T 3,435 feet per second

3-4.5.2. Maximum Range. APFSDS-T (MK 258) 25,400 yardsAPFSDS-T (MK 268) 25,400 yardsHEI-T 8,800 yardsMPLD-T 8,600 yardsTP-T 9,200 yards

Figure 3-17 30 Millimeter Target Practice, Traced (TP-T) (MK239)

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3-5.1. General. This section describes character-istics of all of the 40mm ammunition cartridges currently in the Navy 2T cog inventory except for the 40mm grenade cartridges listed in SW010-AD-GTP-010. The 40mm ammunition is issued in the form of a "fixed" or completely assembled car-tridge in which the cartridge case is crimped around the base of the projectile. This arrangement permits handling of the projectile and propelling charge as one unit. The 40mm cartridge is used in a rapid-fire, automatic gun, fed by an automatic mechanism into which four-round charger clips are hand-loaded. The gun can be fired in a rapid-fire or single-shot mode. The cartridges are identified and issued as follows:

3-5.2. Ammunition/Interface.

3-5.2.1. The 40mm blank saluting charges are used in the MK 11 saluting gun mount.

3-5.3. Ammunition Characteristics.

a. The shape, weight, and ballistics of all of the 40mm service cartridges are approximately the same.

b. The firing pin of the gun strikes the percus-sion primer and ignites the black powder in the primer tube.

3-5.4. Propelling Charge. The propelling charges (Figure 3-18) for 40mm ammunition are assembled in either MK 2 brass or MK 3 steel car-tridge cases. The cartridge case is attached rigidly to the projectile by means of a 360-degree crimp. The propelling charge consists of a percussion primer (MK 22), 326.6 grams of M1 propellant, and 5 grams of lead foil.

3-5.4.1. Blank Saluting Charge. These charges are used to render salutes and other honors. The 40mm saluting charge is being established as the standard Navy saluting charge. Since no projectile is involved in such firing, the charge consists of a shortened MK 2 or MK 3 cartridge case, black powder, a plug, and a primer (MK 22 MOD 1). There are three 40mm saluting charges in the inventory; the major difference among these is the amount of black powder. See Table 3-7.

3-5.4.1.1. DODIC B650. This is now the stan-dard saluting charge (Figure 3-19) filled with 200 grams of loose black powder with the plug situated down in the case against the powder.

CARTRIDGE ABBREVIATION DODIC

Blank saluting charge (350 g)

— B545


— B650


— B550

Figure 3-18 40 Millimeter Propelling Charge Assembly

Figure 3-19 40 Millimeter Blank Saluting Charge, DODIC B650 (200 g.)

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3-5.4.1.2. DODIC B550. This is the light report saluting charge (Figure 3-20) filled with 50 grams (bagged) of black powder specifically for firing in the Washington Naval District.

3-5.5. Packing. The ammunition is handled and shipped according to OP 4 and OP 5. The ammu-nition and container are painted, marked, and let-tered according to WS 18782. The following bulk packaging requirements apply:


Projectile Propelling Charge TotalWeight

(kg)Cartridge Assembly DODIC Body Explosive

Filter Tracer Fuze Cartridge Case Primer Propellant Wt.

(g. Nominal)

Blank Saluting B545 -- -- -- -- MK 2 Brass MK 3 Steel

MK 22 Perc Black Powder350 g

0.953



0.767



0.857

Figure 3-20 40 Millimeter Blank Saluting Charge, DODIC B550 (50 g.)

NALC TYPE PALLETIZING PACKING

B545 Blank Saluting MIL-STD-1323/264 DWG 1583362



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3-6.1. General. The 57mm 70 caliber (HE-3P) cartridge is a high explosive round designed for self defense against a variety of air and surface targets. See Table 3-8. It is used in the MK 110 MOD 0 57mm Naval Gun System that is designed by Bofors of Sweden but built in the US by BAE. The system firing rate is nominally 220 round per minute. The system uses the High-Explosive, Pre-fragmented, Programmable, Proximity (HE-3P), or the TP car-tridges.

The HE-3P cartridge can operate against a vari-ety of targets because of the multiple fuzing options available. Because of the fuzing options, it can func-tion safely in a heavy, ECM environment. The car-tridge is designed to be more resistant to accidental initiation than conventional cartridges and provides increased lethality.

The TP cartridge is the same weight and balance as the HE-3P cartridge, except that an inert projectile is substituted for the explosive-loaded projectile, but the same propelling charge is used. The TP projec-tile simulates the performance of the explosive loaded projectile in flight.

3-6.2. Ammunition Characteristics.

3-6.2.1. HE-3P Cartridge. The HE-3P car-tridge consists of a propelling charge subassembly and an explosive-loaded and fuzed projectile assembly with a weight of about 13.4 pounds and an overall length of 26 inches. The propelling charge is joined to the projectile by crimping the cartridge case mouth to the projectile body.

3-6.2.1.1. Projectile. The projectile consists of a steel body, threaded at the nose to receive the 3P fuze, and through which, the projectile is loaded.

No liner is used to separate the fuze from the explosive load. The projectile has a tapered boat-tail, a solid base, and a metal rotating band, as is common. Although the projectile exterior appears normal, the ogive is formed by a metal shell, under which, is a layer of 2400 tungsten spheres compris-ing more than a pound which give the projectile superior fragmentation characteristics.

The projectile is loaded with a PBX-type of explosive (roughly 80% HMX and 20 percent polyurethane) that has the consistency of a hard rubber. This makes the projectile less sensitive to shock, fragmentation, cook-off and other stimuli that might be seen in service use.

The explosive-loaded projectile cartridge uses a fuze that can be programmed for up to six func-tion modes by means of direct current (DC) and a pulsed high-frequency (HF) message at the fuze setter.

The 3P fuze operates as a conventional prox-imity fuze (when fired unprogrammed), or as a proximity fuze during a particular time interval of flight. Time settings are also available. An impact function is resident after arming throughout the trajectory, in all modes except the armor-piercing (AP) mode. The various modes, and the type of target they might be used against are listed in Table 3-9. The 3P fuze is programmed as it is laterally fed from the gun magazine to the shift tongue. When the gun is initially loaded with ammunition, the first round transferred to the shift tongue does not receive a program-ming, therefore, the first round will function in the default Proximity mode.


CARTRIDGE ABBREVIATION NSN NALC

Cartridge, High Explosive, Pre-fragmented, Programmable, Proximity (HE-3P) fuzed round, MK 295 MOD 0

HE-3P 1310-01-533-0235 BA22

Cartridge, Target Practice (TP) round, MK 296 MOD 0

TP 1310-01-533-0239 BA23

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During the course of fire, the HE-3P round that remains on the shift tongue awaiting the next firing command will have been programmed with the previous course of fire programmed fuze mode. The 3P fuze can be expected to retain the fuze pro-gramming for up to 10 minutes and to function as programmed. When that time has expired, the round can either be fired and function in default Proximity mode or can be passed by the fuze setter to receive another program.

3-6.2.1.2. Propelling Charge. The propelling charge consists of an electrical primer loaded with black powder, a brass cartridge case and the Low Vulnerability Ammunition (LOVA) propellant. The cartridge case has thin panels located in the sidewalls of the cartridge case that act as vents to prevent gas buildup, if the propelling charge is somehow ignited. This, coupled with the insensi-tive LOVA propellant (nitramine-based), makes the cartridge less susceptible to accidental initiation than conventional cartridges.

3-6.2.2. TP Cartridge. This cartridge consists of the same propelling charge as described above, as well as a projectile that is designed to be ballistically-similar to the fight characteristics of

the HE-3P cartridge. The projectile is of steel construction and filled with an inert material. A steel nose plug seals the projectile. The projectile simulates the weight and other physical characteristics of the HE-3P projectile and allows the TP projectile to duplicate the flight of the explosive-loaded HE-3P cartridge.

The cartridges are packaged, two each, in the MK 806 MOD 0 container (Figure 3-21) and are held together with the MK 8 MOD 0 clip (Figure 3-22). Thirty MK 806 MOD 0 containers, banded to the MK 12 MOD 1 pallet, form the unit load. Explosive weights for the cartridges are listed in Table 3-10.

3-6.3. Ballistic Data. The ballistic data for this cartridge is listed as follows:

BALLISTIC DATA*

Muzzle Velocity 3419 feet per second

Maximum Range 9.05 miles

* Manufacturer’s Data

Table 3-9 57 Millimeter 70 Caliber Mode and Target Type

Mode Target

Gated Proximity Function Air Defense

Gated Proximity function with impact priority Air Defense-Large Targets

Time function Small fast maneuvering surface craft and concealed onshore targets

Impact function Surface

Amour Piercing Surface

Proximity mode (when fired unprogrammed) (Not Applicable)

Table 3-10 57 Millimeter Explosive Weights

DESIGNATOR FUZE HIGH EXPLOSIVE PROPELLING CHARGE

MK 295 MOD 0 MK 442 00.93 pounds PBX-Type 2.77 Lbs

MK 296 MOD 0 N/A N/A

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Figure 3-21 MK 806 Container

Figure 3-22 M8 Clip

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3-20


3-7.1. General.The 76mm, 62-caliber cartridge is a high-explo-

sive round designed for self-defense against a wide variety of air and surface targets. Variable time ammunition with infrared (IR), radio frequency (RF), or controlled variable time (CVT) fuzes and point detonating cartridges are available. The ammunition is issued in the form of a fixed, com-pletely assembled round, referred to as a cartridge, and is identified and issued as follows:

3-7.2. Ammunition/Interface. The 76mm ammunition is used in the MK 75 fully automatic gun mount, which is mated to the MK 92 fire control system. The MK 75/76mm gun mount is known as

the 76mm, 62 caliber Oto Melara Compact Automatic Gun Mount. 3-7.3. Ammunition Characteristics.

THE 76MM, 62 CALIBER AMMU-NITION IS PERCUSSION PRIMED; DO NOT REMOVE FROM STORAGE TANKS UNTIL READY TO PLACE IN REVOLV-ING MAGAZINE. AVOID STRIK-ING THE PRIMER AGAINST ANY OBJECT.

The 76mm, 62 caliber cartridge is a fixed round of ammunition consisting of a propelling charge assembly and an explosive loaded and fuzed projectile assembly. The propelling charge and projectiles are joined by crimping the cartridge case mouth to the rotating band of the projectile. The propelling charge assembly is common to all the cartridges. Functional differences between cartridges result from differences in fuzing and/or projectile filler. Table 3-11 presents a summary of the ammunition data.

3-7.3.1. Projectiles. Introduction of new pro-jectile configurations provide increased versatility of the 76mm cartridge. The projectiles are described in the following subordinate paragraphs.

3-7.3.1.1. High Explosive, Infrared (HE-IR). The HE-IR projectile (Figure 3-23 and Figure C-11) consists of a hollow steel (AISI 9260) body, threaded at the nose to receive a passive infrared fuze, which provides a fragmentation capability against aircraft and surface targets. The body has a solid base and a tapered boattail with a gilding metal rotating band. The projectile body is filled with Composition A-3 explosive. A fuze cavity liner is installed in the explosive cavity to separate the fuze from the explosive. A felt pad is placed between the explosive and the fuze cavity liner to allow for thermal expansion of the explosive.

CARTRIDGE ABBREVIATION DODICHigh explosive, controlled variable time

HE-CVT C066

High explosive, infrared

HE-IR C060


HE-IR C112

High explosive, point detonating

HE-PD C061


HE-PD C113

High explosive, variable time

HE-VT C059

Target practice—nonfragmenting variable time

VT NON-FRAG C058

Nonrammable dummy

Dummy C118

Rammable dummy Dummy C097Gaging – C063Blind loaded and plugged

BL-P C062

Clearing charge – C116

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3-7.3.1.2. High Explosive, Point Detonating (HE-PD). The HE-PD projectile (Figure 3-23) is typical of the HE-IR (see paragraph 3-7.3.1.1.), the difference being that this projectile is fuzed with a PD fuze.

3-7.3.1.3. High Explosive, Variable Time (HE VT). The HE-VT projectile (Figure 3-23) is simi-lar to the HE-IR projectile, the difference being that this projectile is fuzed with a variable time (proximity) fuze and contains only composition A-3. Also, this configuration is produced without a cavity liner. In this case, a bituminous coating com-pound is used to coat the explosive surface.


Projectile Propelling ChargeTotal

Weight (lb.)

(Approx.)Cartridge Assembly DODIC Type Fuze

Explosive Filler Propellant Filler

Primer CartridgeCaseType Wt.

(lb.) Type NominalWt. (lb.)

MK 166 C113 HE-PD MK 407 CompA-3

1.3 M6+2 5.35 MK 161 76mm/62 Brass or

steel

26.60

MK 165 C112 HE-IR MK 404 CompA-3

1.3 M6+2 5.35 MK 161 76mm/62 Brass or

steel

26.60

MK 197 C118 Dummy - inert - inert - inert 76mm/62 Brass or

steel

26.60

MK 199 C060 HE-IR MK 404 CompA-3

1.3 M6+2 5.35 MK 161 76mm/62 Brass or

steel

26.60

MK 200 C061 HE-PD MK 407 CompA-3

1.3 M6+2 5.35 MK 161 76mm/62 Brass or

steel

26.60

MK 201 C062 BL-P - Inert - M6+2 5.35 MK 161 76mm/62 Brass or

steel

26.60

MK 202 C058 TP-VT-NON-FRAG

MK 417 CBU-Gray

- M6+2 5.35 MK 161 76mm/62 Brass or

steel

26.60

MK 207 C097 Dummy - Inert - - - - 76mm/62 Brass or

steel

26.60

MK208 C059 HE-VT MK 417 CompA-3

1.3 M6+2 5.35 MK 161 76mm/62 Brass or

steel

26.60

MK 230 C066 HE-CVT M732 CompA-3

1.3 M6+2 5.35 MK 161 76mm/62 Brass or

steel

26.60

MK 76 C116 ClearingCharge

- - - M6+2 5.35 MK 161 76mm/62 Brass or

steel

13.00

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.

3-7.3.1.4. Target Practice, Variable Time Non-fragmenting (TP VT-NONFRAG). The TP VT-NONFRAG projectile (Figure 3-24) is designed for use in antiaircraft target practice, particularly against expensive drone targets, for observing the firing results, frequently without loss of the drone. A standard projectile body is filled with inert mate-rial around the color burst unit to obtain the desired weight. The nose of the projectile is fused with a VT-RF proximity fuze. The color burst is ignited through the action of the nose fuze.

3-7.3.1.5. Blind Loaded and Plugged (BL-P). Blind loaded cartridges should be loaded as the first cartridge in the feeder magazine to be fired first. This practice allows firing through the muzzle covers used to protect such gun barrels from the weather. It also prevents premature initiation of a live-loaded projectile fuze by ice or water in the gun barrel when the gun must be quickly put in action. Under no circumstances should a projectile with a PD fuze be fired through any muzzle cover. The standard projectile body (Figure 3-25) is filled with inert material to bring it within the weight tolerance of the service projectile. The nose is fitted with an inert (dummy) fuze. These cartridges are for target practice, ranging, and proving ground tests.

3-7.3.1.6. Nonrammable Dummy. The non-rammable dummy cartridge consists of a modified projectile body, a dummy nose plug, a steel or brass cartridge case, an inert primer, and dummy propellant. The projectile body and cartridge case are spot welded together. The nonrammable dummy cartridges are used to exercise gun crews in loading and testing the gun's ammunition han-dling system, except for ramming.

3-7.3.1.7. Rammable Dummy. The rammable dummy cartridge consists of a modified projectile body dummy nose plug and a steel cartridge case. The projectile and case are held together by a steel rod extending through the case and threaded into the primer hole. A series of urethane shock springs are attached to the steel rod to absorb the shock developed during ramming. The rammable dummy cartridges are used in testing the gun's ammunition handling systems, including ramming.

3-7.3.1.8. Gaging Cartridge. The gaging car-tridge is a precision-machined steel gage cartridge used for adjustment of the ammunition feed system of Gun Mount MK 75. The gaging cartridge is not to be used as a dummy cartridge.

3-7.3.2. Propelling Charge. The propelling charge (Figure 3-26) consists of a steel cartridge case of a conventional, straight-taper design, assembled with a percussion primer (MK 161 MOD 0), and M6+2 propellant, lead foil used as a decoppering agent, a cardboard distance piece, and a polyethylene wad. The cartridge case is attached rigidly to the projectile by means of a 360-degree crimp. The steel case replaced the original brass case used in the initial production.

Figure 3-23 76 Millimeter High Explosive Projectile (Point Detonating or Proximity)

Figure 3-24 76 Millimeter Target Practice, Variable Time-Nonfragmenting Projectile

Figure 3-25 76 Millimeter Blind Loaded and Plugged Projectile

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3-7.3.3. Clearing Charge (short charge). The clearing charge (Figure 3-27) uses all components common to the propelling charge assembly except that the cartridge case is shortened 3.5 inches prior to assembly and a second polyethylene wad is inserted on the top of the shortened distance piece in place of a projectile. The full assessed propel-lant load is used to ensure adequate pressure to reset even a worn gun. The cartridge case is short-ened to permit chambering behind a lodged projec-tile during a clearing operation.

3-7.4. Packing. The ammunition is handled and shipped according to OP 4 and OP 5. The ammu-nition is packed according to Ordnance Require-ment (OR) 68/36, painted, marked, and lettered according to WS 18782. The following palletizing requirements apply:

3-7.5. Ballistic Data. The ballistic data for this cartridge are listed as follows:

3-7.5.1. Average Muzzle Velocity. The aver-age muzzle velocity is 3,000 feet per second.

3-7.5.2. Maximum Range. The maximum range is 17,505 yards.

Figure 3-26 76 Millimeter Propelling Charge

Figure 3-27 76 Millimeter Clearing Charge

NALC TYPE REQUIREMENT

C058 VT-NONFRAG

MIL-STD-1323/263

C059 HE-VT MIL-STD-1323/263C097 Dummy

(Rammable)MIL-STD-1323/263

C060 HE-IR MIL-STD-1323/263C061 HE-PD MIL-STD-1323/263C062 BL-P MIL-STD-1323/263C066 HE-CVT MIL-STD-1323/263C112 HE-IR MIL-STD-1323/263C113 HE-PD MIL-STD-1323/263C116 Clearing

ChargeMIL-STD-1323/263

C118 Dummy (Non-Rammable)

MIL-STD-1323/263

SW030-AA-MMO-010

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3-8. 5-INCH, 54 CALIBER AMMUNITION

3-8.1. General. The 5-inch, 54 caliber ammuni-tion described in this chapter fits within the sepa-rated ammunition category since the projectile and the propelling charge are two separate components, but they are loaded with the gun chamber in a sin-gle operation (i.e., one-ram cycle). See Appendix C for Ammunition Fact Sheets by projectile MK and MOD. The 5”/54 conventional ammunition can be used in either 5”/54 or 5”/62. A complete round of ammunition consists of the projectile and a propelling charge that is packed, shipped, and issued separately. This system is used as a tactical weapon against surface and air targets and for shore bombardment.

3-8.2. Projectile Inventory. The basic configurations of projectiles in the 5-inch, 54 caliber ammunition inventory are as follows:

3-8.3. Ammunition/Interface. The 5-inch, 54 caliber ammunition is used in the MK 45 Single LW (lightweight) gun mount with a MK 19 barrel. The gun’s rate of fire is 20 rounds per minute. The primer is electric and the firing pin in the breech does not directly strike the primer. It is located in the breech and extends slightly from the breech face. It scrapes lightly across the cartridge case base as the breech closes, leaving a dimple in the base. The dimple seen in the firing pin on fired rounds is made by the recoiling cartridge case pushing against the firing pin.

3-8.4. Ammunition Characteristics. The 5-inch, 54 caliber ammunition has been upgraded through product improvement and developed for increased range, lethality (high-fragmentation

PROJECTILE ABBREVIATION DODIC

High explosive, controlled variable time

HE-CVT D350/D295/D346/D803/

DA37High explosive, point detonating

HE-PD D330/D343/D884/DA38

High explosive, mechanical time/point detonating

HE-MT/PD D338/D340


HE-IR D342/D327

High explosive, variable time

HE-VT D331/D332/D347

High capacity (HE), point detonating

HC D320/D339

Antiaircraft (HE), mechanical time

AAC D319

Rocket assisted (HE), controlled variable time

RAP D325

Common, base detonating, spotting dye

COM D322

Illuminating, ILLUM D328/D353/D354

White phosphorus (smoke), mechanical time

WP/MT D313

White phosphorus (smoke), point detonating

WP/PD D314

Target practice (puff), mechanical time

TP-Puff D291

Target practice (puff), point detonating

TP-Puff D290

Target practice nonfragmenting, variable time

VT-NON-FRAG D333/D334

Target practice (puff)

TP-Puff D351

Chaff dispensing, mechanical time

Chaff D311/D312

Blind loaded and plugged

BL-P D341/D349

PROPELLING CHARGE DODIC

Full charge, universal, poly plug D326Reduced charge, flashless, poly plug D297Clearing D296Dummy D308


SW030-AA-MMO-010

3-25

steels), increased effectiveness with better fuzing, improved logistics by standardizing interfaces, and increased safety.

3-8.4.1. Projectiles. The projectiles used in the 5-inch, 54 caliber ammunition are described in the following subordinate paragraphs.

3-8.4.1.1. High Explosive. These general pur-pose projectiles (Figure 3-28) are used primarily to provide blast and fragmentation. In addition, the high-fragmentation projectile has been optimized for use against soft targets (personnel in particular). The projectile can be fuzed with either an impact, a time, or a proximity fuze. The proximity-fuzed projectiles are fitted with fuze liners to permit interchanging of the nose fuze (ashore only) with-out remote equipment. The projectiles designated as HE-CVT, HE-PD, HE-MT/PD (Figure C-15, Figure C-16 and Figure C-17); HE-IR, or HE-VT do not have base fuzing. The weights of the pro-

jectiles vary slightly depending upon explosive/fuze combination used. The bodies of each of these projectiles are essentially the same except for the base. The principal variations in these high explosive projectiles are described below.

Figure 3-28 5-Inch, 54-Caliber High Explosive Projectile

Table 3-12 5-Inch, 54-Caliber Projectile Fuze Information Indexed by MK and MOD

AURMK

AURMOD DODIC NSN FUZE NOSE

MK/MODFUZE TYPE ADF BASE NOMINAL

WEIGHT

6 0 D336 1320-00-038-8783 DNP NONE NONE SOLID 70.00

6 0 D336 1320-00-038-8784 DUMMY 25 MT NONE SOLID 70.00

6 1 D336 1320-00-213-3832 INERT 342 MT NONE BFHP 70.00

6 2 D336 1320-00-213-3833 DNP NONE NONE BFHP 70.00

80 0 D330 1320-01-007-0821 30/5 PD 395/0 SOLID 67.63

80 7 D330 1320-01-073-5662 30/3.5 PD 395/0.1 BFHP 68.91

80 9 D330 1320-01-084-0306 30/ALL PD 395/ALL SOLID 68.99

81 0 D346 1320-01-161-7500 M732 CVT NONE SOLID 68.16

82 0 D340 1320-01-028-4943 393/0 MT/PD NONE SOLID 68.15

88 2 D353 1320-01-088-7928 342/1 MT 396/0 BASE PLUG 71.80

90 0 D314 1320-00-504-2617 30/5 PD 396/0 BASE PLUG 69.04

91 0 D354 1320-01-096-9465 342/1 MT 396/0 BASE PLUG 63.92


96 0 D291 1320-01-077-4276 342/1 MT 54/2 BFHP 69.82

97 2 D290 1320-01-077-4277 30/5 PD 54/2 BFHP 68.94

100 1 D334 1320-01-013-3173 73/13 VT NONE SOLID 69.40

100 2 D334 1320-01-256-0709 416/0 VT NONE SOLID 69.40

107 0 D327 1320-01-180-7411 91/1 IR NONE BFHP 70.40

107 1 D327 1320-01-005-3960 91/1 IR NONE SOLID 70.40

SW030-AA-MMO-010

3-26

108 1 D339 1320-01-023-9665 399/0 PD/D NONE SOLID 69.63

108 2 D339 1320-01-120-3995 407/1 PD/D NONE SOLID 69.06


116 0 D317 1320-01-176-9605 73/13 VT NONE BFHP 70.00

116 1 D332 1320-01-023-9667 73/13 VT NONE SOLID 69.71

116 2 D332 1320-00-123-7812 73/11 VT NONE SOLID 69.71

117 1 D331 1320-00-518-3941 73/10 VT SD NONE SOLID 69.71

118 0 D334 1320-01-103-5123 INERT 342 MT NONE BFHP 69.71

118 1 D336 1320-01-103-5124 DNP NONE NONE BFHP 69.80


127 0 D295 1320-01-064-2664 M728/360 CVT NONE SOLID 69.80

128 0 D351 1320-01-301-6368 393/0 MT/PD NONE BFHP 68.60

156 1 D327 1320-01-350-4221 404/1 IR NONE BFHP 70.69

156 5 D327 1320-01-350-4218 404/1 IR NONE SOLID 69.00

157 0 D350 1320-01-350-8052 M732 CVT NONE BFHP 69.32

157 2 D350 1320-01-350-4219 M732 CVT NONE SOLID 68.69

158 0 D803 1320-01-350-0236 M732 CVT NONE SOLID 68.69

160 0 D884 1320-01-370-3695 407/1 PD/D NONE SOLID 69.12

165 0 DA01 1320-01-390-3293 404/1 IR NONE BFHP 69.45

170 0 DA06 1320-01-435-0432 404/MODS IR NONE SOLID 69.55

173 0 D338 1320-01-426-3175 393/0 MT/PD NONE SOLID 68.39

174 1 DA08 1320-01-451-3637 419/0 MF NONE SOLID 69.38

179 0 DA34 1320-01-506-7609 432/0 ET NONE SOLID 67.25

182 0 DA15 1320-01-459-9779 432/0 ET NONE BASE PLUG 70.99

Table 3-12 5-Inch, 54-Caliber Projectile Fuze Information Indexed by MK and MOD (Continued)

AURMK

AURMOD DODIC NSN FUZE NOSE

MK/MODFUZE TYPE ADF BASE NOMINAL

WEIGHT

Table 3-13 5-Inch, 54-Caliber Projectiles Indexed by DODIC and NSN

DODIC NSN AURMK

AURMOD TYPE BODY

MK/MODEXPLOSIVE FILLER

MK/MOD

D290 1320-01-077-4277 97 2 PUFF-PD 61/ALL REACTANT UNIT

D291 1320-01-077-4276 96 0 PUFF-MT 61/ALL REACTANT UNIT

D295 1320-01-064-2664 127 0 HE-CVT 64/1 COMP A-3

D314 1320-00-504-2617 90 0 WP-PD 48/1 MK 14 LOAD

D317 1320-01-176-9605 116 0 HE-VT 41/0 COMP A-3

D327 1320-01-005-3960 107 1 HE-IR 64/0, 1 COMP A-3

D327 1320-01-180-7411 107 0 HE-IR 41/0 COMP A-3

D327 1320-01-350-4216 156 5 HE-IR 64/0 COMP A-3

SW030-AA-MMO-010

3-27

D327 1320-01-350-4221 156 1 HE-IR 41/0 COMP A-3

D330 1320-01-007-0821 80 0 HE-PD 64/0 COMP A-3

D330 1320-01-073-5662 80 7 HE-PD 61/0 EXPL D

D330 1320-01-084-0306 80 9 HE-PD 64/ALL EXPL D

D331 1320-00-518-3941 117 1 HE-VT SD 64/0 COMP A-3

D332 1320-00-123-7812 116 2 HE-VT 64/0 COMP A-3

D332 1320-01-023-9667 116 1 HE-VT 64/0, 1 COMP A-3

D334 1320-01-013-3173 100 1 NONFRAG-VT 64/0, 1 COLOR BURST

D334 1320-01-256-0709 100 2 NONFRAG-VT 64/1 COLOR BURST

D336 1320-00-038-8783 6 0 DUMMY CAST BRONZE INERT

D336 1320-00-038-8784 6 0 DUMMY CAST BRONZE INERT

D336 1320-00-213-3832 6 1 DUMMY 41 MODIFIED INERT




D338 1320-01-426-3175 173 0 HE-MT/PD 64/0, 1 COMP A-3

D339 1320-01-023-9665 108 1 HE-PD/D 64/0, 1 COMP A-3

D339 1320-01-120-3995 108 2 HE-PD/D 64/1 COMP A-3

D340 1320-01-028-4943 82 0 HE-MT/PD HIFRAG PBXN-106

D341 1320-01-028-4942 109 1 HE-BL&P HIFRAG INERT


D346 1320-01-161-7500 81 0 HE-CVT HIFRAG PBXN-106

D349 1320-00-480-3389 92 1 BL&P 64/0,1 INERT

D350 1320-01-350-4219 157 2 HE-CVT 64/0 COMP A-3

D350 1320-01-350-8052 157 0 HE-CVT 41/0 COMP A-3

D351 1320-01-301-6368 128 0 PUFF-MT/PD 61/0 REACTANT UNIT

D353 1320-01-088-7928 88 2 ILLUM-MT 48/1 MK 11/0 ILLUM LOAD

D354 1320-01-096-9465 91 0 ILLUM-MT 48/1 MK18/0 ILLUM LOAD

D803 1320-01-350-0236 158 0 HE-CVT 64/2 PBXN-106

D884 1320-01-370-3695 160 0 HE-PD/D 64/2 PBXN-106

DA01 1320-01-390-3293 165 0 PUFF-IR 61/1 REACTANT UNIT

DA06 1320-01-435-0432 170 0 NONFRAG-IR 64/ALL COLOR BURST

DA08 1320-01-451-3637 174 1 HE-MF 64/2 PBXN-106

DA15 1320-01-459-9779 182 0 KE-ET CARGO INERT. TUNGSTEN

DA34 1320-01-506-7609 179 0 HE-ET HIFRAG PBXN-106

Table 3-13 5-Inch, 54-Caliber Projectiles Indexed by DODIC and NSN (Continued)

DODIC NSN AURMK

AURMOD TYPE BODY

MK/MODEXPLOSIVE FILLER

MK/MOD

SW030-AA-MMO-010

3-28

Table 3-14 5-Inch, 54-Caliber Projectile Fuze Information Indexed by DODIC and NSN

DODIC NSN AURMK

AURMOD

FUZE NOSE MK/MOD

FUZE TYPE ADF BASE NOMINAL

WEIGHT

D290 1320-01-077-4277 97 2 30/5 PD 54/2 BFHP 68.94

D291 1320-01-077-4276 96 0 342/1 MT 54/2 BFHP 69.82

D295 1320-01-064-2664 127 0 M728/360 CVT NONE SOLID 69.80

D314 1320-00-504-2617 90 0 30/5 PD 396/0 BASE PLUG 69.04

D317 1320-01-176-9605 116 0 73/13 VT NONE BFHP 70.00

D327 1320-01-005-3960 107 1 91/1 IR NONE SOLID 70.40

D327 1320-01-180-7411 107 0 91/1 IR NONE BFHP 70.40

D327 1320-01-350-4218 156 5 404/1 IR NONE SOLID 69.00

D327 1320-01-350-4221 156 1 404/1 IR NONE BFHP 70.69

D330 1320-01-007-0821 80 0 30/5 PD 395/0 SOLID 67.63

D330 1320-01-073-5662 80 7 30/3.5 PD 395/0.1 BFHP 68.91

D330 1320-01-084-0306 80 9 30/ALL PD 395/ALL SOLID 68.99

D331 1320-00-518-3941 117 1 73/10 VT SD NONE SOLID 69.71

D332 1320-00-123-7812 116 2 73/11 VT NONE SOLID 69.71

D332 1320-01-023-9667 116 1 73/13 VT NONE SOLID 69.71

D334 1320-01-013-3173 100 1 73/13 VT NONE SOLID 69.40

D334 1320-01-256-0709 100 2 416/0 VT NONE SOLID 69.40

D336 1320-00-038-8783 6 0 DNP NONE NONE SOLID 70.00

D336 1320-00-038-8784 6 0 DUMMY 25 MT NONE SOLID 70.00

D336 1320-00-213-3832 6 1 INERT 342 MT NONE BFHP 70.00

D336 1320-00-213-3833 6 2 DNP NONE NONE BFHP 70.00

D336 1320-01-103-5124 118 1 DNP NONE NONE BFHP 69.80


D338 1320-01-426-3175 173 0 393/0 MT/PD NONE SOLID 68.39

D339 1320-01-023-9665 108 1 399/0 PD/D NONE SOLID 69.63

D339 1320-01-120-3995 108 2 407/1 PD/D NONE SOLID 69.06

D340 1320-01-028-4943 82 0 393/0 MT/PD NONE SOLID 68.15


D344 1320-01-103-5123 118 0 INERT 342 MT NONE BFHP 69.70

D346 1320-01-161-7500 81 0 M732 CVT NONE SOLID 68.16


D350 1320-01-350-4219 157 2 M732 CVT NONE SOLID 68.69

D350 1320-01-350-8052 157 0 M732 CVT NONE BFHP 69.32

D351 1320-01-301-6368 128 0 393/0 MT/PD NONE BFHP 68.60

D353 1320-01-088-7928 88 2 342/1 MT 396/0 BASE PLUG 71.80

D354 1320-01-096-9465 91 0 342/1 MT 396/0 BASE PLUG 63.92

D803 1320-01-350-0236 158 0 M732 CVT NONE SOLID 68.69

SW030-AA-MMO-010

3-29

3-8.4.1.1.1. High Explosive, Controlled Vari-able Time (HE-CVT). This projectile is avail-able with either a high-fragmentation steel body (D346) or a conventional steel body (D350 or D295). See Figure C-10 and Figure C-13. The high-fragmentation body projectile was designed primarily for use against personnel and light sur-face targets. The HE-CVT can be used in the anti-aircraft role in an emergency; however, the reliability is lower than VT- or IR-fuzed projectiles in this mode. For those projectiles loaded with Composition A-3, the nose of the projectile body is threaded internally and fitted with a conventional, VT-RF proximity and AD fuze. The fuze is sepa-rated from the Composition A-3 explosive load by a cavity liner to permit fuze replacement (ashore only) without remote equipment. The base of the projectile is either plugged or solid. The new con-figurations are loaded with either PBXN-106 (D803, D346) or PBXN-9 (DA37) and display improved sensitivity characteristics. The explosive load of the high-fragmentation version (D346) is sealed from the short intrusion CVT fuze with an aluminum lid, thereby permitting contact fuze replacement (ashore only). The explosive load in the conventional steel body version is sealed by a boostered fuze adapter containing either PBXN-106 (D803) or PBXN-9 (DA37) sealed by an alu-minum lid, thereby permitting contact fuze replacement (ashore only). The adapter is fitted with a short intrusion CVT fuze.

3-8.4.1.1.2. High Explosive, Point Detonating (HE-PD). The nose of this projectile body is threaded internally for an AD fuze adapter that is fitted with a PD and AD fuze, with or without a cavity liner. See Figure C-5. The PD/D version

with composition A-3 uses a standard adapter fitted with a short intrusion PD/D fuze. The low-fragmentation steel body with a Composition A-3 explosive-loaded projectile was designed for use against surface targets vulnerable to an impact burst. The high-fragmentation projectile (D343) and the new version of the conventional steel projectile (D884) is loaded with PBXN-106. The newest version of the conventional steel projectile (DA38) is loaded with PBXN-9. The base of the projectile is either plugged or solid.

3-8.4.1.1.3. High Explosive, Mechanical Time/Point Detonating (HE-MT/PD). This high-frag-mentation projectile (D340) or conventional pro-jectile (D338) is fitted with a nose fuze that has the capability of functioning in either a mechanical time or a point detonating mode. The point deto-nating mode acts as a backup mode if the fuze impacts before the preset time has elapsed. The body is filled with either PBXN-106 (D340) or Composition A-3 (D338). The base of both types are solid.

3-8.4.1.1.4. High Explosive, Infrared (HE-IR). This conventional, Composition A-3 explosive-loaded projectile (D327) is designed exclusively for use against infrared-emitting airborne targets. The nose of the projectile body is threaded inter-nally and fitted with a VT-IR proximity fuze that has an integral auxiliary detonating fuze. A point detonating feature is also incorporated into the nose fuze in the event the target is missed. The fuze is separated from the explosive load to permit fuze replacement (ashore only) without remote equipment. The base of the projectile is either plugged or solid. See Figure C-18 in Appendix C.

D884 1320-01-370-3695 160 0 407/1 PD/D NONE SOLID 69.12

DA01 1320-01-390-3293 165 0 404/1 IR NONE BFHP 69.45

DA06 1320-01-435-0432 170 0 404/MODS IR NONE SOLID 69.55

DA08 1320-01-451-3637 174 1 419/0 MF NONE SOLID 69.38

DA15 1320-01-459-9779 182 0 432/0 ET NONE BASE PLUG 70.99

DA34 1320-01-506-7609 179 0 432/0 ET NONE SOLID 67.25

Table 3-14 5-Inch, 54-Caliber Projectile Fuze Information Indexed by DODIC and NSN (Continued)

DODIC NSN AURMK

AURMOD

FUZE NOSE MK/MOD

FUZE TYPE ADF BASE NOMINAL

WEIGHT

SW030-AA-MMO-010

3-30

3-8.4.1.1.5. High Explosive, Variable Time (HE-VT). This projectile is designed for use against targets that are vulnerable to air-burst. The nose of the projectile body is threaded internally and fitted with a VT-RF proximity fuze, which is supplemented by a booster. A self-destruct capa-bility is incorporated into the nose fuze of D316 and D331 projectiles, but is omitted in D317 and D332 projectiles. The nose fuze is separated from the Composition A-3 explosive load by a cavity liner to permit fuze replacement without remote equipment. The base of the projectile is either plugged or solid.

3-8.4.1.1.6. High Explosive, Multi-Function Fuze (HE-MF). This projectile features a conven-tional MK 64 (solid base) projectile body with a PBXN-106 explosive main charge, a PBXN-106 loaded boostered fuze adapter sealed with an alu-minum lid that permits contact fuze replacement (ashore only) and the MK 419 Multi-Function Fuze. This is a multiple capability round that can be set in either a proximity mode for air targets, timed for a required height of burst or impact initi-ated. The fuze function is selected immediately prior to firing via the MK 34 fuze setter.

3-8.4.1.1.7. Kinetic Energy, Electronic Time (KE-ET). The kinetic energy projectile is designed for short to intermediate range ship self defense against HSMST threats. The round consists of a Cargo-type projectile body and threaded base plug, approximately 9,000 inert tungsten alloy shell shot pellets, aluminum spacers, expelling charge, and a highly accurate electronic time fuze. When functioned, the round produces a concentrated pattern of tungsten pellets that is directional along the range axis and is very effective against armored surface craft.

3-8.4.1.2. High-Fragmentation (HI-FRAG).

HI-FRAG PROJECTILES DROPPED LESS THAN 5 FEET SHALL BE EXAMINED CAREFULLY FOR JOINT SEPARATION AND DAMAGED

ROTATING BANDS. PROJECTILES DROPPED MORE THAN 5 FEET SHALL BE DISPOSED OF ACCORDING TO OP 5. ACCIDENTAL DROP OF A PROJECTILE OFTEN RESULTS IN WIDENING OF THE MID-BODY JOINT BETWEEN THE FORWARD AND AFT PROJECTILE HALVES. IF A PROJECTILE IS FOUND WITH A JOINT OPENING, THE ROUND SHOULD BE SET ASIDE FOR RETURN TO AN AMMUNITION ACTIVITY. ACCIDENTAL DROP OF A PROJECTILE MAY RESULT IN A CRACKED OR BROKEN ROTATING BAND. THESE PROJECTILES WARRANT CLOSE BAND INSPECTION. IF A CRACKED OR BROKEN ROTATING BAND IS FOUND, THE ROUND SHOULD BE SET ASIDE FOR RETURN TO AN AMMUNITION ACTIVITY.

The MK 81 HE-CVT and the MK 82 HE-MT/PD projectiles (Figure 3-29) are general purpose rounds, designated for a multitude of tasks includ-ing antiaircraft fire, shore bombardment, and use against unarmored or lightly armored vehicles. These projectiles combine high lethality, extended range, tighter dispersion, and greater freedom from premature firings. Each projectile consists of a two-piece projectile body that has a visible press-fit joint in the central portion. Other distinguishing features include a plastic discarding rotating band, a one-caliber boattail beneath the rotating band, an improved ogive shape, no waterproof protecting cap threads, and a forward and aft bourrelet. The improved aerodynamic shape gives the projectile an extended range capability. The explosive system includes a main charge and a subcharge. Both charges are encapsulated in polyethylene beakers. This allows 100 percent inspection of the charges before assembly as well as ecological disposal upon disassembly. Both of these charges are vac-uum loaded with PBXN-106.

SW030-AA-MMO-010

3-31

The MK 179 HE-ET round is identical to the MK 81 and MK 82 HIFRAG projectiles except for the fuze. The MK 179 uses an Electronic Time Fuze (MK 432) and the round provides short to intermediate range ship defense capability against HSMST threats.

3-8.4.1.3. High Capacity (HC). These low-fragmentation, steel body projectiles (Figure 3-30) are designed for use against unarmored surface tar-gets or shore installations that are vulnerable to impact burst. The projectile nose and base are threaded internally to receive nose and base fuzing. The projectile cavity is filled with either Explosive D or Composition A-3.

3-8.4.1.4. Illuminating (ILLUM). The ILLUM projectile (Figure 3-31) is designed to deploy a parachute suspended pyrotechnic candle for target illumination. The projectile illuminating load and a small black powder explosive charge are sealed

within the mechanical time fuzed projectile by a base plate. When the MT and AD fuzes function, the AD fuze ignites the black powder, which expels the projectile illuminating load. The illuminating composition for the MK 88 projectile is a pow-dered magnesium mixed with an oxidizer that burns for approximately 50 seconds with a candle-power of 600,000 lumens.

3-8.4.1.5. White Phosphorus (WP) (Smoke).

WHITE PHOSPHORUS PROJEC-TILES MUST BE STORED IN AN UPRIGHT POSITION TO PRE-VENT THE WHITE PHOSPHO-RUS FROM LEAKING.

The intended use of the WP projectile (Figure 3-32) is to provide spotting, antipersonnel screen-ing, and limited incendiary effects. It may be used with a PD fuze (D314) or with an MT fuze (D313). When the fuze functions, it sets off the expelling charge, which ignites the delay element and forces the canister (MK 14) from the rear of the projectile. The burster tube of the canister detonates and dis-perses a cloud of white phosphorus approximately 50 yards in diameter and lasts 7 minutes in still air. The tendency of white phosphorus to break into very small pieces that burn rapidly and its low melting point led to coating white phosphorus with synthetic rubber. This coated product is called plasticized white phosphorus (PWP).

Figure 3-29 5-Inch, 54-Caliber High-Fragmentation Projectile

Figure 3-30 5-Inch, 54-Caliber High Capacity Projectile

Figure 3-31 5-Inch, 54-Caliber Illuminating Projectile

SW030-AA-MMO-010

3-32

NOTEBoth WP and PWP can be extinguished by immersion in water. To prevent reig-nition after drying, copper sulfate can be used.

3-8.4.1.6. Target Practice (Puff) (TP-Puff).

THE SMOKE PRODUCED BY THE CHEMICAL MIXTURE USED IN A TARGET PRACTICE (PUFF) PROJECTILE CONTAINS HYDROCHLORIC ACID, WHICH IS EXTREMELY IRRITATING TO THE LUNGS, EYES, AND MUCOUS MEMBRANES. IN THE EVENT SMOKE OR CORROSIVE BUILDUP IS DISCOVERED COM-ING FROM A PUFF PROJECTILE, THE ROUND SHOULD BE DIS-POSED OF SAFELY. THE HAZ-ARDS ASSOCIATED WITH THE SMOKE CAN BE REDUCED WITH A WATER SPRAY. ON-BOARD SHIP, THE ROUND CAN BE DISPOSED OF AT SEA. ON LAND, THE ROUND CAN BE MOVED TO AN OPEN AREA FOR DISPOSAL BY EXPLOSIVE ORD-NANCE DISPOSAL PERSONNEL.

This is a nonexplosive, smoke producing pro-jectile (Figure 3-33), used as a practice (spotting) round. A standard projectile body is filled with inert material around the smoke agent containers. The nose of the projectile is fitted with an MT fuze

(D291) or a PD fuze (D290) and an AD fuze. The inert filled body has a 2-inch-diameter aluminum tube down the center with one metal can or two Teflon bottles of smoke agent potted at the base end with epoxy. The inert load of the projectiles is Filler E, comprised of stearic acid, barium sulfate, dead burned gypsum, and wood resin. The smoke producing chemicals, a 50/50 mixture of vanadium oxytrichloride and titanium tetrachloride, are con-tained in the Teflon bottles or metal cans. The base plug has been modified by removing all but one and one-half threads so that, on fuze function, the threads shear and the base plug and chemicals are expelled through the base of the projectile. The chemicals from the ruptured bottles or metal cans react with the moisture in the air, producing a dense gray smoke cloud that approximates the size of the smoke cloud from a high-explosive round.

3-8.4.1.7. Target Practice, Nonfragmenting (VT-NONFRAG). These projectiles (Figure 3-34and Figure C-8) are designed for use in antiaircraft target practice, particularly against expensive drone targets, for observing the firing results, fre-quently without loss of the drone. A standard pro-jectile body is filled with inert material around the color burst unit to obtain the desired weight. The nose of the projectile is fitted with a VT-RF prox-imity fuze, supplemented either by a fuze booster or an AD fuze. A self-destruct capability is incor-porated into the nose fuze of projectile D333; this self-destruct feature is omitted in projectile D334. A fuze cavity liner separates the fuze from the color burst unit and the inert filler. The color burst is ignited through the action of the nose fuzing and the black-powder pellets. The color burst unit may be one of several colors (red, yellow, or gray). The base of the projectile is either plugged or solid.

Figure 3-32 5-Inch, 54-Caliber White Phosphorus Projectile

Figure 3-33 5-Inch, 54-Caliber Target Practice (Puff) Projectile

SW030-AA-MMO-010

3-33

3-8.4.1.8. Blind Loaded and Plugged (BL-P). Various conventional projectile bodies are filled with inert material to bring them within the weight tolerance of the service projectile. Noses are fitted with dummy nose plugs. Bases are either plugged or solid, as applicable.

3-8.4.1.9. Dummy. The conventional projectile bodies are filled with inert material to bring them within the weight tolerance of the service projec-tile. Before filling the projectile bodies, the rotat-ing bands of the projectiles are machined so that projectile surfaces are flush. Dummy projectiles are used for mount checkout and maintenance. Bases are plugged or solid, as applicable.

3-8.4.2. Propelling Charge. The propelling charge is that component of the complete round that provides the force to propel the projectile from the gun to the target. Cased ammunition prevents the escape of gases toward the breech of the gun. The case expands from the pressure of the burning propellant and forms a tight seal against the gun barrel chamber. The plug and wad are expelled from the muzzle, usually in pieces, just behind the projectile, though they don’t travel far from the gun due to their light weight and non-aerodynamic shapes. Table 3-15 is a listing of variations that are available.

3-8.4.2.1. Full Service Charge. The propelling charge (Figure 3-35 and Figure C-4) consists of a steel cartridge case of a straight taper design. The propelling charge is assembled with the MK 45 primer (electric) and loaded with NACO (Navy Cool) smokeless powder (propellant). A cardboard wad and a bonded polyethylene wad, serve to hold

the propellant in place. Occasionally the charge weight of a given propellant lot is low enough that a cardboard distance piece is required to prevent shifting of the propellant load. A polyurethane clo-sure plug completes the unit.

3-8.4.2.2. Reduced Charge. The external con-figuration of the reduced charge, D297, is the same as the full service charge but its lower propellant weight will be noticed when handling the charge. It definitely includes a cardboard distance piece to prevent shifting of the low weight propellant charge. A MK 153 primer is used for this charge.

3-8.4.2.3. Clearing Charge. The clearing charge (short charge), D296, is similar to the full and the reduced charges, the major difference being that the cartridge case is approximately 12.5 inches shorter. Clearing charges are used to clear guns by firing out projectiles after a propelling charge misfires or a loading jam occurs. The D296 charge has a coned polyurethane or an elastomeric foam closure plug and uses a polyethylene wad bonded to the cartridge case sidewall to retain the propellant.

3-8.5. Packing. The ammunition is handled and shipped according to OP 4 and OP 5. The ammu-nition is painted, marked, and lettered in accor-dance with WS 18782. The following palletizing requirements apply:

Figure 3-34 5-Inch, 54-Caliber Nonfragmenting Projectile

Figure 3-35 5-Inch, 54-Caliber Propelling Charge

PROJECTILE REQUIREMENT

Standard MIL-STD-1323-6HI-FRAG MIL-STD-1323-271Tanking OR-68/43Palletizing MIL-STD-1323/5C

SW030-AA-MMO-010

3-34

The propelling charge is packed in the appro-priate cartridge tank according to the local standard operating procedures.

3-8.6. Ballistic Data. The ballistic data for the 5-inch, 54 caliber projectile are as follows:

3-8.7. Average Muzzle Velocity.

3-8.8. Maximum Range.

PROJECTILE PROPELLINGCHARGE MUZZLE

VELOCITY

MK 41 or MK 64 Full-service (MK 67)

2,650 feet per second

MK 41 or MK 64 Reduced (MK 68)


HI-FRAG Full-service (MK 67)


ALL TYPES Clearing Charge 1,650 feet persecond

PROJECTILE PROPELLING CHARGE RANGE

MK 41 or MK 64 Full-service (MK 67)

25,600 yards

MK 41 or MK 64 Reduced(MK 68)

13,500 yards

HI-FRAG Full-service (MK 67)

25,800 yards

Table 3-15 Current Fleet Issue 5”/54 Caliber Propelling Charges

DODIC NSN AURMK

AURMOD TYPE CASE PLUG PRIMER PROPELLANT

D296 1320-01-056-2826 65 1 Clearing MK 9 MOD 0, 1 Steel Modified

MK 27 MOD 0 MK 48 MOD 2 SPCF

D297 1320-00-766-5824 68 0 Reduced MK 9 MOD 0, 1 Steel MK 9 Cork MK 153 MOD 0 SPDF

D297 132-01-060-1118 68 2 Reduced MK 9 MOD 0, 1 Steel MK 12 MOD 3 Poly

MK 153 MOD 0, 1 SPDF

D308 1320-00-073-6819 8 0 Dummy MK 9 Steel Bronze N/A N/A

D308 1320-00-889-8185 8 1 Dummy MK 9 MOD 0, 1 Steel Bronze N/A N/A

D308 1320-01-055-9974 8 2 Dummy MK 9 Steel Case Steel N/A N/A

D326 1320-01-004-1082 67 3 Full MK 9 MOD 0, 1 Steel MK 12 MOD 3 Poly

MK 45 MOD 1 SPCF

DW46 1320-00-609-2381 6 0 Test MK 6 MOD 0 Brass N/A N/A N/A

DW46 1320-01-180-5538 6 1 Test MK 9 MOD 0, 1 Modified N/A N/A N/A

SW030-AA-MMO-010

4-1

CHAPTER 4

FUZES

4-1. GENERAL

4-1.1. Scope. This chapter describes U.S. Navy gun projectile fuzes that are still in-service. Descriptions of older fuzes can be found in earlier revisions of this document or by contracting the appropriate Engineering Agents.

4-1.2. Introduction. Fuzes provide relative safety for gun projectiles during storage, transpor-tation, handling, and gun firing. They are also used to initiate munition functioning at the desired time or position. Fuze operation is generally divided into two phases, arming and functioning. Mechan-ical, electric, electronic, or magnetic means are used for fuze operation. Navy gun projectile fuzes are devices designed to detonate or ignite an explo-sive filler or initiate the expulsion of a chemical, illuminating, or other load.

Projectiles may contain more than one fuze; and in years past it was not uncommon for one projectile to carry a nose fuze, an AD fuze, and a Base Deto-nating fuze.

Information on proximity fuzes found in SW300-B0-ORD-010 and SW300-B0-ORD-020, formerly NAVSEA OP 1480 has been merged into this document.

4-1.3. General Fuze Arming and Function. The arming cycle of a fuze begins when a projec-tile is fired from a gun. At this time, the physical forces present, the electrical or mechanical devices incorporated in the fuze design, or a combination of forces acting together begin to override safety devices that allow the alignment of sensitive explo-sive elements, such as primers and detonators, with insensitive explosive elements, such as leads and boosters, to form an armed explosive train. The method and duration of fuze arming depend upon design features of the particular type of ammuni-tion; but once a fuze is armed to accomplish its purpose, its parts must remain in the armed posi-tion until completion of the fuze firing cycle. The

functioning of a fuze during its firing cycle depends upon the type of final action the fuze has been designed to accomplish. For example, the final action may be impact firing (instantaneous or after a predetermined delay time after target impact); time firing (immediately upon completing the arming and timing cycle); or proximity firing (approach to the target). Fuzes arm when moti-vated by forces present in the firing of a gun. Spe-cific fuzes use one or more of several of the forces described below and illustrated in Figure 4-1.

4-1.4. Forces Affecting Fuzes. This section describes the principal forces affecting fuzes dur-ing gun firing, flight, and impact. Fuzes must be able to sustain these forces and arm and function correctly. In addition, these forces are often used to sense projectile-launched critical points in projec-tile travel and cause arming and functioning pro-cesses to take place within the fuze. Figure 4-1illustrates some of these forces.

4-1.4.1. Setback. Setback is the linear inertial force that tends to move all fuze parts to the rear as the projectile is accelerated along the gun barrel upon firing of the gun. Setback ceases after the projectile leaves the muzzle. This force is used fre-quently in the arming process by using weights supported by springs.

4-1.4.2. Angular Acceleration. Angular accel-eration produces a tangential inertial torque accom-panying the rate of increase of projectile rotation in the bore of the gun. This torque is proportional to the setback force caused by the twist rate of the barrel rifling. It is of primary importance when part of the fuze is turned to set the fuze. The tan-gential inertial torque produced may overcome the friction torque built into the fuze setting torque joint that is supplemented by friction caused by set-back. When the inertial torque increases, parts slippage may occur resulting in a fuze setting change.

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Figure 4-1 Forces That Work on Fuzes

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4-1.4.3. Balloting. The repeated side slap of a projectile against the inside of the gun barrel as the projectile advances is called balloting. It is partic-ularly severe in worn guns, producing high-g, short-duration shocks that may damage delicate fuze components.

4-1.4.4. Creep. Creep is the continuous inertial force accompanying the deceleration of a projectile in flight caused by air resistance. It tends to move forward those fuze parts not exposed to the air stream. Creep is sometimes referred to as the set forward force and acts in the direction opposite to setback. This force is not constant; it is a function of the velocity of a projectile and the density of the air. Maximum creep occurs at the moment when the propellant gas ceases to accelerate the projec-tile. In some instances, this force is controlled by an anticreep spring to prevent fuze initiation until the projectile strikes the target with sufficient impact to overcome the resistance spring.

4-1.4.5. Centrifugal Force. The force created by the rotation of the projectile is continuous and tends to move all fuze parts radially away from the longitudinal axis of the fuze. The rate of rotation in the gun tube is not constant because of barrel rifling; it is proportional to the linear velocity of the projectile and is greatest at the muzzle. Rota-tion slowly decays in flight at a rate that is not gen-erally proportional to the rate of linear velocity decay. Centrifugal force is used in all major cali-ber projectile fuzes to operate spin detents for unlocking arming devices and, sometimes, firing pins.

4-1.4.6. Friction. Friction is the resistance to relative motion that exists between two bodies in contact. In fuzes that arm by means of centrifugal force, friction is used as a safety feature; e.g., to keep spin detents locked until setback forces fall off at or near the muzzle.

4-1.4.7. Impact. When the projectile strikes the target, moving parts inside the projectile are still under the influence of creep. The sharp decelera-tion of the projectile results in relative motion between fuze parts. On impact, this motion may be used to drive a spring-retained plunger into a primer; the direct force of impact on the nose of the

projectile may be employed to drive a firing pin into a primer; or the shock that accompanies the force of impact may be used to initiate a shock-sen-sitive explosive, with no mechanical assistance.

4-1.4.8. Shock Forces Felt in Worn Guns. In a worn gun using separated ammunition, enlarge-ment at the origin of the bore will cause the high explosive (HE) loaded projectile to seat deeper in the barrel on the trailing edge of the rotating band. This seating geometry results in an increased dis-tance between the propelling charge and the pro-jectile, which results in more severe shock starts from closure plug impact but slightly lower setback forces. In addition, seating on the trailing edge of the rotating band results in severe set forward shocks when the leading edge of the rotating band impacts the rifling after significant forward veloc-ity of the projectile is attained. The abnormally high shock start and rotating band impacts experi-enced in worn gun barrels sometimes lead to higher dud rates or premature bursts.

4-1.5. Explosive Components in Fuzes. The explosive train of a fuze is an arrangement of a series of combustible and explosive elements con-sisting of a primer, detonator, delay, relay, lead, and booster charge, one or more of which may be either omitted or combined. These elements are arranged in a sequence, which is characteristic of all fuze explosive trains. When proceeding from the initial to the last element of the train, the size and gener-ally the explosive effect of the elements increase while their sensitivity to initiation decreases.

4-1.5.1. Primer. The primer, if present, is the initial explosive train component in the fuze and is intended to produce flame and hot gases when ini-tiated. The primer mixture may be initiated by either mechanical or electrical energy. Mechani-cally initiated primers are classified as stab or per-cussion, depending on the method of initiation. Stab primers are initiated by penetration of a sharp-pointed firing pin through the primer closure disc into the priming mixture. Percussion primers are exploded by the pinching or crushing of the explo-sive between the anvil and the primer cup. Electric primers are initiated by sparking current through the explosive.

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4-1.5.2. Detonator. The fuze detonator may be the initial or the intermediate element of the explo-sive train. When the detonator is the initial ele-ment, it is usually a stab or electric detonator and is designed to deliver its detonating impulse to the next explosive after being pierced by a firing pin. Flash detonators are sometimes used as the inter-mediate element in the explosive train, and are designed to deliver a detonating impulse to the next explosive train component after receiving a heat or shock impulse generated by a previous primer or detonator.

4-1.5.3. Delay. The delay is an explosive train component that introduces a controlled time delay in the functioning of the explosive train. Black powder and lead styphnate are the most commonly used materials in the delay elements.

4-1.6. Relay. The relay is a component that adds explosive force to a detonating impulse of a prior explosive component and, thus, reliably initiates a succeeding explosive component.

4-1.6.1. Lead. The lead is a component in fuzes located between a detonator and a booster charge or, in some projectiles, between a detonator and an expelling charge, which may be part of the projec-tile assembly. The lead is designed to transmit the detonator impulse to the booster/expelling charges. There may be more than one lead; for example, a lead-out from the detonator with a separate lead-in to the booster/expelling charges.

4-1.6.2. Booster/Expelling Charges. The booster charge, if present, is the last component of the fuze explosive train and increases many times the impulse from a detonator or lead so as to reli-ably detonate the main charge of the projectile. An expelling charge replaces the booster in an illumi-nating, a nonfragmenting, and other Cargo rounds.

4-2. POINT DETONATING (PD) FUZES

4-2.1. Fuze MK 27 MOD 1 (40mm Point Deto-nating).

4-2.1.1. General. The MK 27 MOD 1 fuze is a PD nose fuze, designed to arm by centrifugal force and to fire upon impact with a target (Figure 4-2). A spin of 166.7 to 233.3 revolutions per second is required to arm the fuze.

4-2.1.2. Description. In the MOD 1, the metal firing pin is held in place by two hourglass-shaped detents that are retained by a circular band-type spring. The ends of the band-type spring overlap, allowing for its expansion. Above the firing pin housing is a plastic extension or hammer that seats in the metal firing pin. The rotor, with lead coun-terweights and detonator, is assembled in the rotor block with the axis of the detonator inclined at an angle of 55 degrees to the longitudinal axis of the fuze. The line of center between the lead counter-weights is at an angle of about 35 degrees to the longitudinal axis of the fuze. The rotor is held in this unarmed position by the two rotor detents, whose tapered ends engage holes in the side of the rotor.

4-2.1.3. Operation. Upon firing of the gun, setback causes the firing pin to move aft against the hourglass detents. Because of their shape, the detents will not spin outward in the gun barrel while setback forces acting on the firing pin are present. Therefore, the firing pin will remain locked until the projectile leaves the barrel and comes under the influence of an aerodynamic decelerating (set forward or creep) force. The cen-trifugal force that arms the fuze accomplishes the following:

a. The hourglass detents are moved outward against the band-type spring, freeing the firing pin.

b. The rotor detents are moved against their respective springs, freeing the rotor.

c. The lead counterweights turn the rotor until they are at a maximum radius from the axis of rotation of the fuze. In this position, the detonator is aligned with the firing pin and booster. The rotor is retained in this position of equilibrium by cen-trifugal force. Upon impact with an object offering sufficient resistance, the plastic hammer is driven aft, propelling the firing pin. The firing pin stabs the detonator, causing it to fire, and thereby initi-ates the booster lead-in and booster.

4-2.1.4. Safety Features. The components that affect the safety of this fuze are the firing pin and rotor detents, the plastic firing pin extension, and the counterweighted rotor. The operations that set these features into action are the following:

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a. On setback, the shoulder on the firing pin moves aft against the hourglass detents. The set-back force on the firing pin holds the tapered sides of the detents against the firing pin housing until setback force is overcome by creep force. The time interval afforded by this action prevents early detonation in the gun bore.

b. The plastic firing pin extension is designed as a safety device in the event the fuze is acciden-tally dropped. Should this happen, the plastic extension will break, but the fuze may remain ser-viceable; whereas, a one-piece metal firing pin might force its way past the detents, jam the rotor and cause the round to be a dud.

c. The rotor assembly and firing pin are each held in the unarmed position by detents that are withdrawn only when acted upon by considerable centrifugal force. Centrifugal force is also neces-sary to move the counterweighted rotor to its armed position. If the detonator in the rotor should fire in the unarmed position, it would not detonate the lead or booster charge.

4-2.1.5. Use.

40mm HE, HEI projectiles

4-2.1.6. Physical Characteristics.

SpecificationMIL-F-18698Drawing .................................................300423Weight............................................0.234 poundLength ........................................... 2.452 inchesThread size..................................1.180-14NS-2Intrusion depth ..................................0.545 inch

4-2.1.7. Explosive Components. Detonator ................MK 18 MOD 0; lead azide

primer mix and lead azide

Booster...................... Tetryl

4-2.1.8. Arming.No arm ................ 167.7 revolutions per secondArm..................... 233.3 revolutions per second

4-2.1.9. Function.Type ................................................ MechanicalDelay............................................InstantaneousTarget sensitivity................. 0.040 in aluminum

0.138 in chipboard

4-2.1.10. Packing. In projectile.

Figure 4-2 Fuze MK 27 MOD 1 (Point Detonating), Unarmed and Armed Positions, Cutaway Views

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4-2.2. Fuze MK 30 (5” Point Detonating).

DO NOT USE POINT DETONAT-ING FUZE MK 30 MODS 2 AND 3 IN HEAVY RAIN. EARLY BURSTS CAN OCCUR. USE MK 30 MOD 5 INSTEAD.

4-2.2.1. General. The MK 30 is a PD nose fuze(Figure C-3). An interrupter-mechanism safety device blocks the flash channel between the nose detonator and the relay detonator when the fuze is not armed. Early MODs were sensitive to water impact and are obsolete. MK 30 PD fuzes are shipped form the depot and installed in projectiles with the setting screw in the OFF position. When

set to the OFF position, the spring-loaded inter-rupter shown in the cross-sectional views of Fig-ures 4-3 and 4-4 bears against one shoulder on the setting sleeve and is locked in position, blocking the flash tube between the nose detonator and the relay detonator in the base. In this condition, if the nose detonator is set off accidentally or the projec-tile is fired, the interrupter prevents the flash from reaching the relay detonator, and the fuze duds.

The MK 30 PD fuze is armed by centrifugal force and fired by impact. MODs 2, 3, and 4 of the MK 30 PD fuze detonate on 1/2 inch-thick ply-wood and the MOD 5 on 2-inch-thick plywood. All MODs detonate on 1/8 inch-thick mild steel, water, or soft and hard terrain at angles as shallow as 8 degrees from the target surface, provided the projectile does not ricochet.

Figure 4-3 Fuze MK 30 MOD 3 (Point Detonating), Unarmed, Cross-Sectional View with Setting Screw in OFF Position

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4-2.2.2. Description.

4-2.2.2.1. MK 30 MOD 3. The MK 30 MOD 3 (Figure 4-3) differs from MOD 2 in that the MOD 3 has a thin aluminum safety disc inserted between the relay detonator and the aft end of the flash tube.

4-2.2.2.2. MK 30 MOD 4. Unlike the MK 30 MODs 2 and 3, the MOD 4 has a thin steel ogive. Internally it is identical to the MOD 3. It is not used on projectiles; it is used only on spin-stabi-lized rockets.

4-2.2.2.3. MK 30 MOD 5. The MK 30 MOD 5 (Figure 4-4) differs from MODs 2, 3, and 4 in that it incorporates a rain baffle assembly in the fuze nose and a stop pin in the setting assembly. The rain baffle assembly is built into a cavity 3/4-inch deep by 1/2-inch wide in front of the firing pin. The rain baffle assembly consists of three stag-gered crossbars, placed one behind the other inside a cavity, that break up raindrops. This feature pre-vents the fuze from functioning early in heavy rain-fall because of impact of large raindrops against the firing pin. Any accumulation of rain in the cav-ity is forced out by projectile spin and airflow through four small holes drilled at the base of the cavity. In addition, this feature gives the fuze the capability of penetrating jungle foliage without materially reducing its impact sensitivity. The stop pin prevents the setting screw from being turned clockwise beyond the ON position as well as from being turned counterclockwise beyond the OFF position.

4-2.2.3. Operation. When the fuze is fired in the OFF position, it will be a dud. The ON position provides SQ point detonating action. When set to the ON position, the interrupter operates by centrif-ugal force against the action of its spring and moves outward into the setting sleeve, unblocking the flash tube. This action takes place after the projectile has left the gun. The interrupter arms the fuze at 25 to 33.3 revolutions per second. On impact, the firing pin support collapses and the fir-ing pin is driven into the nose detonator. The flash from the nose detonator passes down the flash tube and initiates the relay detonator. This causes the AD fuze to function and explode the main charge of the projectile. The MODs 2 and 3 of the MK 30

PD fuze detonate on 1/2 inch-thick plywood and the MOD 3 RFM and MODs 4 and 5 on 1 inch-thick plywood. All MODs detonate on 1/8 inch-thick mild steel, water, or soft and hard terrain at angles as shallow as 8 degrees from the target sur-face, provided the projectile does not ricochet. The MK 30 MOD 3 also detonates on airborne cork fragments from the muzzle blast of a nearby gun.

4-2.2.4. Safety Features. This fuze has only one primary feature, the interrupter. An additional safety feature of lesser importance is the aluminum safety disc between the after end of the flash tube and the plastic relay detonator holder in all MODs since MOD 2. If the nose detonator is set off acci-dentally, its gas pressure, which occasionally leaks past the unarmed interrupter, would have to punc-ture the safety disc before it could set off the relay detonator. This can only occur if the fuze is in a spin environment. The rain baffle in MOD 3 RFM and MODs 4 and 5 may also be considered a safety feature., since it prevents the fuze from functioning early because of heavy rainfall.

4-2.2.5. Fuze Setting Instruction.

THE FUZE SETTING SCREW IN FUZE MK 30 MODS 2, 3, AND 4 DOES NOT PROVIDE A POSITIVE STOP AT THE FUZE ON POSITION, AND CONSE-QUENTLY UNDESIRED DUDS MAY OCCUR IF THE SETTING SCREW IS ACCIDENTALLY ROTATED CLOCK-WISE BEYOND THE VERTICAL (12 O’CLOCK – 6 O’CLOCK) ON POSI-TION. IT IS IMPERATIVE THAT, WHEN SETTING FUZES TO THE ON POSITION, THE SCREWDRIVER SLOT IS TURNED TO BE AS PARALLEL TO T H E F U Z E A X IS A S P O S S I B L E, ALIGNED WITH THE ON-SQ MARK-INGS ON THE FUZE OGIVE.

FOR PD FUZES BEING RETURNED TO STORAGE AFTER BEING PREVI-OUSLY SET TO THE ON POSITION, A COUNTERCLOCKWISE ROTATION BACK TO THE STOP AT THE HORI-Z O N T A L ( A P P RO X I M A T E L Y 9 O’CLOCK – 3 O’CLOCK) OFF POSI-TION IS REQUIRED.

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Normally, the MODs 2, 3, and 4 are set in the OFF position with one end of the setting slot at approximately 9 o’clock. (Because of an inconsis-tency of the location of the stop, the setting slot will be found between 9 o’clock and 10 o’clock.) For SQ impact burst, set the fuze (using a screw-driver) by turning the setting screw clockwise to the ON position (at 12 o’clock, plus or minus 5 degrees). Screw travel is through an arc of less than 90 degrees. See Figure 4-5. MODs 2, 3, and 4 have setting screws with the appearance of the left-hand view of Figure 4-6. When the setting slot is aligned vertically with the axis formed by ON and SQ, the fuze is capable of functioning super-quick at impact. MOD 5, as shown in the right-hand view of Figure 4-6, has OFF and ON mark-ings and an arrow to indicate the direction and rota-tional distance the screw is to be turned. The ON position provides SQ point detonating action.

4-2.2.6. Use.5-inch, HE, WP projectiles

4-2.2.7. Physical Characteristics.MOD 5

Specification..................................WS 12048Drawing............................................2501615

WeightMODs 2, 3, and 4 ....................... 1.38 poundsMOD 5 ....................................... 1.27 pounds

Length (all MODs) ......................... 4.57 inches

Figure 4-4 Fuze MK 30 MOD 5 (Point Detonating), Unarmed and Armed Cross-Sectional Views

Figure 4-5 Fuze MK 30 MODs 2-4, and MK 66 MOD 0 (Point Detonating), Incorrect and

Correct Fuze Settings

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.

4-2.2.8. Explosive Components.Nose detonator MODs 2 and 4...............MK 25 MOD 0; lead

azide primer mix and lead azide MODs 3 and 5............. MK 25 MOD 1; NOL

130, lead azideRelay detonator... MK 29 MOD 0; lead azide

Thread size.............................. 1.700-14NS-1

Intrusion depth MODs 2, 3, and 4............................ 0.81 inch MOD 5.......................................... 0.803 inch

4-2.2.9. Arming.No arm...................... 25 revolutions per secondArming .................. 33.3 revolutions per secondDelay .........................................................None

4-2.2.10. Function.Type.................................................MechanicalDelay ........................................... InstantaneousSensitivity

MODs 2, 3, and 4.................... 0.5-inch woodMOD 5............................... 2.0-inch plywood

4-2.2.11. Packing.48/box; 1.7 cubic feet.

4-2.3. Fuze MK 399 MOD 0 (5” Point Deto-nating/Delay).

4-2.3.1. General. The MK 399 MOD 0 PD/D fuze (Figure 4-7) is a product improvement of the older MK 30 PD fuze. It also incorporates the delay arming and booster features of the MK 395 AD fuze and delayed initiation feature of the MK 64 BD fuze. This nose fuze is complete within itself, needing no auxiliary detonating or base fuzes as separate components.


4-2.3.2.1. Design Features. Fuze MK 399 is designed to initiate detonation of high explosive projectiles for full and reduced charges. The fuze intrusion dimension (2.210-inch maximum) and external contour conform to MIL-STD-333 for short intrusion fuzes, 75mm and larger. Fuze MK 399 functions instantaneously on target impact when set for PD. The delay capability is always active as a backup in case instantaneous action fails to occur. When set in delay mode, the (instanta-neous) capability is blocked and the fuze can pro-vide only delayed function after impact. The delay period is designed to be 0.006 to 0.013 second and is not subject to adjustment. Fuze MK 399 is pro-vided with a rain shield over the firing pin, permit-ting use in adverse weather conditions where rainfall rates up to approximately 6 inches per hour

Figure 4-6 Fuze MK 30 MODs 2 3 and 4 (Left) and MOD 5 (Right) (Point Detonating), External View

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are encountered. The point detonating assembly is sufficiently insensitive to allow foliage penetration without functioning, but will initiate upon impact with water, earth, 0.250-inch-thick aluminum, mild steel at angles up to 45 degrees, and 2.0-inch-thick wood targets. The heavily constructed and hard-ened fuze body permits penetration of light armor and earthwork fortifications allowing advanta-geous use of the delay mode. The fuze is not designed for use against heavily armored targets as the fuze has internal structural limitations and the associated projectiles have insufficient strength for true armor piercing use. Attempted use against heavily armored targets generally results in instan-taneous functions regardless of mode selection.

4-2.3.2.2. Safety Functions. Fuze MK 399 con-tains the MK 41 MOD 0 Delay Arming Safety Device (DASD) which provides inbore and safe separation safety functions. The fuze is safe until it is 360 feet from the gun. The fuze is armed and functional at a maximum distance of 550 feet from the gun. This is the same DASD previously used in the MK 395 AD fuze with functional character-istics being unchanged. There is an anti-mal-assembly feature to ensure that the rotor is in the unarmed position at assembly.

Figure 4-7 Fuze MK 399 MOD 0 (Point Detonating), Cross-Sectional and External Views

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4-2.3.2.3. Components. The main components of the fuze are the point detonating assembly, flash channel and relay block assembly, delay selector, delay selector indicator, MK 41 DASD, lead block assembly, booster assembly, body, and head. The head incorporates the rain shield as an integral fea-ture and contains the point detonating assembly that in turn contains the firing pin and MK 25 deto-nator. The flash channel and relay block assembly contains MK 29 detonator, WOX-83A detonator, black powder time delay, Primer MK 101 MOD 3, several flash channels and a cavity for the delay selector. The delay selector is seated in the flash channel and relay block assembly with the delay selector indicator keyed to it and extending through the fuze body. The delay selector indicator seats against a retainer washer that displays the PD and DELAY markings for mode selection. The MK 41 DASD contains a MK 23 detonator mounted in an out-of-line rotor that is held by two spring-loaded detents and retarded by a delay gear train. The lead block assembly contains two MK 8 explosive leads (CH-6) and a setback pin that extends into the DASD to block the rotor. The booster assembly contains the CH-6 explosive booster pellet. The body serves to mount or contain all of the above components and assemblies.

4-2.3.3. Operation. This fuze is designed to operate in one of two modes, PD (instantaneous or SQ) with delay function backup or DELAY mode only. Both modes rely upon the point detonating assembly for initiation at target impact.

4-2.3.3.1. Arming. Upon firing, the setback pin is retracted into the lead block assembly and locked there by angular acceleration. The rotor detents in the MK 41 DASD are withdrawn because of cen-trifugal force that completes the release of the rotor. The off-center rotor provides drive torque, because of centrifugal force, to allow alignment of the explosive train. The rotor is driven to the armed position where it locks, but arming is delayed approximately 0.2 second by action of the delay gear train. This provides a minimum safe separation of 360 feet prior to fuze arming.

4-2.3.3.2. Impact. Upon impact with a substantial target, the rain shield is broken away and the nose portion of the head partially collapses, allowing the firing pin to crush its support and

initiate the MK 25 detonator in the point detonating assembly. The MK 25 detonator fires through a short flash channel into the top of the flash channel and relay block assembly where it initiates the MK 29 detonator.

4-2.3.3.3. Instantaneous Mode. The MK 29 detonator fires into two flash channels in the flash channel and delay block assembly. One flash chan-nel leads directly to the delay subassembly; the other flash channel leads through the delay selector to the rotor of the MK 41 DASD. When the fuze is set on PD, the delay selector presents an open flash channel and the MK 29 detonator initiates the MK 23 detonator in the MK 41 DASD. The delay subassembly initiates simultaneously from MK 29 detonator, serving as a backup mode should direct initiation of the MK 41 DASD fail for any reason.

4-2.3.3.4. Delay Mode. When the delay selector is set on DELAY, the direct flash channel from the MK 29 detonator to the MK 41 DASD is blocked. The MK 29 detonator in this case, serves only to initiate the delay subassembly. The MK 29 detona-tor fires through a short flash channel to the delay firing pin assembly. A shear wire is broken, and the delay firing pin is driven into MK 101 MOD 3 primer, causing its initiation. The MK 101 MOD 3 primer fires through a baffle to the black powder pellet causing it to ignite. The time delay is obtained due to the burn time of the black powder pellet. When the delay pellet burns through, 0.006 to 0.013 second, it initiates the WOX-83A detona-tor that leads through a short flash channel to the MK 23 detonator in the MK 41 DASD rotor.

4-2.3.3.5. Detonator MK 23 Operation. The MK 23 detonator in the MK 41 DASD is initiated by one of the two modes described above. It in turn initiates the first MK 8 explosive lead in the lead block assembly. The second MK 8 lead is ini-tiated by the first, providing an output to the booster assembly. The CH-6 booster then provides sufficient explosive output to initiate the explosive load in the projectile.

4-2.3.4. Safety Features. The MK 23 MOD 1 detonator in the MK 41 MOD 0 DASD is held out of alignment with the rest of the explosive train until arming. The MK 41 MOD 0 DASD is posi-tively blocked in the unarmed position until the set-

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back pin is lowered into the lead block assembly by setback force. The MK 41 MOD 0 DASD rotor is locked in the unarmed position by centrifugal force in flight. The rotor of the MK 41 MOD 0 DASD is connected to a delay gear train that is driven by centrifugal force. This provides approximately 0.2-second arming delay corresponding to a mini-mum of 360 feet safe separation from the gun.

4-2.3.5. Moistureproofing. O-ring seals are installed under the head, delay selector indicator, and booster cup flange to prevent the entrance of moisture into the fuze interior.

4-2.3.6. Use.5-inch, HE projectiles

4-2.3.7. Physical Characteristics.MOD 0 Specification ................................. WS 14104 Drawing ........................................... 2512724 Weight.........................................2.64 pounds Length ........................................5.955 inches Thread size.............................2.00-12UN-2A

Intrusion depth .............................2.21 inches

4-2.3.8. Explosive Components.Detonator.................MK 25 MOD 1; NOL 130

mixture consisting of antimony sul-fide, barium nitrate, lead azide, basic lead styphnate and tetracene; lead azide, base charge

Relay detonator ...... MK 29 MOD 0; lead azideDelay assembly Primer .....................MK 101 MOD 3; primer

mixture consisting of antimony sul-fide, barium nitrate, basic lead styphnate and tetracene

Delay....................Compressed black powder Detonator ...........WOX-83A; lead azide onlyMK 41 DASD Detonator .............MK 23 MOD 1; NOL 130

mixture consisting of antimony sul-fide, barium nitrate, lead azide, basic lead styphnate and tetracene; primer charge lead azide; base charge tetryl

Explosive lead (2) ......... MK 8 MOD 0; each containing two equal increments of CH-6

Booster assembly Dwg 2512435...........CH-6

4-2.3.9. Arming.Setback No arm................................................ 900 g's Arm ................................................. 1,385 g'sSpin No arm.................. 50 revolutions per second Arm ................... 66.7 revolutions per secondDelay............................................ 360 feet, min

4-2.3.10. Function.Type ................................................MechanicalDelay................................. 6 to 13 milliseconds

4-2.3.11. Packing.8/container; 28 pounds; 0.32 cubic foot

4-2.4. Fuze MK 407 (5” and 76mm Point Deto-nating/Delay).

4-2.4.1. General. The MK 407 MOD 0 and MOD 1 PD/D fuzes have manually set, superquick or delay actions. In the PD mode, they provide instantaneous burst upon target impact and have a short pyrotechnic delay as a backup. In the delay mode, the MK 407 has the same delay after impact, for effective penetration of medium-hard targets. The fuzes meet the 76mm projectile weight and contour requirements of MIL-STD-333.

4-2.4.2. Description. The MK 407 MOD 0 fuze (Figure 4-8) has the same explosive train as the MK 399 MOD 0 fuze and is used only in the 76mm, 62 caliber gun system. Part of the steel body around the ogive of the MK 399 fuze was replaced by a plastic ring to reduce the fuze weight to meet the 76mm weight requirement of 2.1 pounds. The MOD 1 (Figure 4-9) replaces the MK 399 MOD 0 and MK 407 MOD 0 fuzes and is used in the 76mm, 62 caliber and 5-inch. There are four major differences between the MOD 0 and MOD 1 fuzes: (a) the MK 29 relay detonator was relocated to the PD/D selector switch assembly; (b) the black powder delay assembly was changed to lead styphnate; (c) the hardened AISI 4140 alloy

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steel body was changed to cold drawn, medium carbon steel, and (d) the MK 41 DASD was changed to the MK 49 MOD 0 and later MK 49 MOD 1 DASD. The MK 49 DASD provides the same safe arming distance as the MK 41; however, it is attached to the lead block before assembly to the fuze body and part of the armed fuze anti-mal-assembly feature, a pin, was relocated to the fuze body. An armed MK 49 DASD can be detected at the final assembly stage because of rotor interfer-ence with the pin in the fuze body. Two changes have been made to the MK 407 MOD 1 fuze since its initial production. These were made to improve reliability of the fuze firing in the correct mode. The original MK 25 MOD 1 stab detonator was modified by eliminating the thick cup at its output end. In addition, the MK 49 MOD 1 DASD replaced the MK 49 MOD 0. The MOD 1 DASD has a less sensitive flash detonator, the MK 50 MOD 0. The arming delay distance depends on the type of gun barrel (advance per revolution). This fuze does not arm in less than 300 feet. Both MODs have the same rain shield over the firing pin as the MK 399 MOD 0. This provides safe use with rain rates as high as 6 inches per hour. The point detonating assembly is sufficiently insensi-tive to allow penetration of light to medium foliage without functioning, but will initiate on water, earth, metal or wood target impact. The hardened fuze body in the MOD 1 permits penetration of light armor and earthwork fortifications, allowing advantageous use of the delay mode. The PD/D selector switch can be turned with a screwdriver or a coin.

4-2.4.3. Operation. On firing, the setback pin behind the MK 49 DASD rotor is retracted into the lead block and locked down by spin. The rotor detents in the DASD are withdrawn by spin, allowing it to turn to the armed position and lock. Arming is delayed by the gear train escapement. On impact, the rain shield breaks away, the nose partially collapses, and the firing pin initiates the stab detonator. Flash from the stab detonator, passes through the flash channel. In the MOD 0 fuze, the MK 29 relay detonator is located at the dividing point of a two-leg flash tube and initiates from the flash of the first detonator. The flash from the MK 29 detonator initiates the delay assembly on one side of the flash tube manifold. After 8

milliseconds, output from the delay assembly flashes to the DASD, initiating the rotor detonator, which was aligned with the end of the flash tube during arming and, in turn, fires the two MK 8 leads and booster pellet. When the PD mode is selected, an interrupter in the other leg of the flash tube is removed and a hole in the interrupter is aligned with the flash tube. Output from the MK 29 detonator flashes down the other flash tube through the hole, instantaneously firing the detonator in the DASD rotor and the remaining components in the firing train. In the MOD 1 fuze, the MK 29 relay detonator is located in the PD/D mode selector switch assembly, in place of the hole, and fires only when the switch is set to the PD mode. Setting the fuze PD aligns the MK 29 in the flash tube and permits its initiation by the flash from the stab detonator. If the MOD 1 fuze is set to the delay mode, the path through the relay detonator is effectively interrupted, preventing it from firing and limiting flash propagation through the delay assembly in the other leg of the flash tube. The MOD 0 fuze uses an older black powder type delay, like the MK 399 MOD 0 fuze; while the MOD 1 fuze uses a more accurate lead styphnate delay.

4-2.4.4. Use.MK 407 MOD 0

76mm, 62 caliber projectilesMK 407 MOD 1 76mm, 62 caliber HE projectiles

5-inch, HE and HI-FRAG projectiles

4-2.4.5. Physical Characteristics.MOD 0 Specification..................................WS 14919 Drawing............................................2513944MOD 1 Specification..................................WS 18888 Drawing............................................5177549Weight............................................ 2.10 poundsLength ........................................... 5.955 inchesThread size................................ 2.0-12UNS-2AIntrusion depth ................................ 2.21 inches

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Figure 4-8 Fuze MK 407 MOD 0 (Point Detonating - Superquick/Delay), Cutaway and External Views

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4-2.4.6. Explosive Components.Stab detonator

MOD 0 and early production MOD 1MK 25 MOD 1; NOL 130 mix and lead azide

MOD 1 recent production (Dwg 558121) .........................NOL 130 mix

and lead azideRelay detonator ...... MK 29 MOD 0; lead azide

(see text for variations in locationand operation)

Delay assembly

MOD 0 ................... MK 101 MOD 3 primer, black powder pellet, and WOX-83A detonator (Dwg 3192110)

MOD 1 .......... Dwg 5177539; NOL 130 mix, lead styphnate, lead azide, and FA 878 mix

Flash detonator in rotor MOD 0 ...................... MK 41 MOD 0 DASD

containing MK 23 MOD 1 detonatorMOD 1 early production .................... MK 49

MOD 0 DASD containing MK 23 MOD 1 detonator

Figure 4-9 Fuze MK 407 MOD 1 (Point Detonating/Delay), Cross-Sectional View

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MOD 1 current production ... MK 49 MOD 1 DASD containing MK 50 MOD 0 detonator

Explosive lead (2)............ MK 8 MOD 0; CH-6Booster ................... Dwg 2512435; 11 g, CH-6

4-2.4.7. Arming.Setback

No arm ..............................................900 g's All arm...........................................1,385 g'sSpin No arm ................50 revolutions per second All arm................75 revolutions per secondArming distance from muzzle 76mm, 62 caliber ....................310 feet, min 3-inch, 50 caliber ....................312 feet, min 5-inch ......................................360 feet, min

4-2.4.8. Function.PD mode...................................... Instantaneous

(delay backup)Delay mode MOD 0 .......................... 6 to 13 milliseconds MOD 1 ............................ 4 to 9 milliseconds

4-2.4.9. Packing.8/container; 23 pounds; 0.32 cubic foot

4-2.5. Fuze M505A3 (Point Detonating).

4-2.5.1. General. The M505A3 fuze is a single-action, superquick fuze (Figure 4-10) intended to function on impact with aircraft targets. The fuze contains an out-of-line detonator to provide mechanical bore safety. The M505A3 is a modifi-cation of the M505A2 fuze. The modifications are significant and were done to resolve problems inherent with the basic fuze and the A1 and A2 variations. The M505A3 fuze has replaced all pre-vious variations and is the only variation of the M505 in production. It is currently used in 20- and 25mm high-explosive ammunition.

Figure 4-10 Fuze M505A3 (Point Detonating), Cutaway and External Views

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4-2.5.2. Description. The fuze consists of a body assembly, a rotor assembly, and a booster assembly. The body assembly consists of an alu-minum firing pin contained in a steel body and covered by a sheet steel cover or nose cap. The rotor assembly consists of a steel rotor containing an M57A2 detonator. A C-shaped rotor detent spring is fitted into a machined groove about the rotor. This assembly is placed in the body cavity so that the rotor detent spring is opposite the annu-lar groove and the detonator is out of line to pro-vide mechanical bore safety. The booster assembly, which consists of a steel holder and explosive charge, is screwed into the base of the fuze body.

4-2.5.3. Use.20mm projectiles25mm projectiles

4-2.5.4. Physical Characteristics.Specification................................MIL-F-46580Drawing............................................... 7258863Weight .............................................. 335 gramsLength ........................................... 1.243 inchesThread size ............................... 0.5625-32NS-1Intrusion depth ....................... 0.378 inch, max.

4-2.5.5. Explosive Components.Detonator................ .M57A2; n-lead styphnate,

Lead azide, HMXBooster ....................................... HMX or RDX

4-3. MECHANICAL TIME (MT AND MT/PD) FUZES

4-3.1. General Mechanical Time Fuze Func-tion. The MT and MT/PD fuzes are designed to initiate the payload of a projectile at a predeter-mined time after the gun is fired. These fuzes are located in the nose of the projectile. A typical MT fuze is shown in Figure 4-11. The MT fuzes con-sist basically of a clock mechanism that releases a firing pin after the time set on the fuze. They are used in high-explosive, illuminating, white phos-phorus, and chaff projectiles. There are basically two types of mechanical time fuzes: MT only and MT/PD, which have selectable MT or PD, as well as a PD backup when set in the MT mode. MT

fuzes are used with an AD fuze and sometimes with a BD fuze. The AD fuze provides extra safety and the proper output charge for the particular pro-jectile. MT/PD fuzes can be used alone or may need the addition of an AD fuze. No base fuze is required with the MT/PD fuze. MT/PD fuzes may have integral delay arming devices, thereby elimi-nating the need for a separate AD fuze.

4-3.2. Fuze Setting. Mechanical time fuzes are usually set automatically by the fuze setter in the 5-inch, MK 45, gun mount. In an emergency the fuzes can be set manually with the appropriate fuze wrench. In the newer MK 45 mount, the fuzes are set by engagement with a pair of slots located also on the lower cap and the body of the fuze. Fuzes not fired are manually reset to S (safe), except MT/PD fuzes that are reset to PD, with the appropriate fuze-setting wrench.

4-3.3. Components. A typical MT fuze consists of four major units as follows.

4-3.3.1. Body. The body contains most of the explosive components including the S&A device, if present. The body also provides an interface to the lower cap, and it anchors the timer.

4-3.3.2. Lower Cap. The lower cap, also called the rotating cap, is attached to the body at the torque joint. This joint allows rotational motion between the lower cap and the body when the fric-tion in the joint is overcome and the fuze is set. The tension or slip torque of the joint is adjusted during assembly of the fuze. The older MT fuzes use a tensioning wire acting through grooves in the cap and body. The tension is adjusted by radial set-screws. The new MT fuzes and MT/PD fuzes use a compressible wave spring. Slip torque is adjusted when the lower cap is threaded to the body and pinned in place. The cap is inscribed on its after outside edge with a scale graduated in seconds to indicate the setting.

4-3.3.3. Upper Cap. The upper cap is threaded to the lower cap to complete the contour of the fuze. The gaskets, when used between the upper and lower caps and the body, are for moisture-proofing. In MT only fuzes, the upper cap is hol-low. In MT/PD fuzes, this cap contains the PD assembly, which consists of a stab detonator, firing

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pin, and either a crush cup or spin detents that sup-port the firing pin above the detonator. When spin detents are used, creep forces keep the firing pin

from resting on the detonator after the spin detents have opened.

Figure 4-11 Typical Mechanical Time Fuze, Cutaway View

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4-3.3.4. Movement Assembly. This assembly comprises the clockwork, the setting, and the firing mechanism. It is attached to the inside of the body by screws. See Figure 4-12. The movement assembly may be divided into three main parts as described in the following paragraphs.

4-3.3.4.1. Timing Disc Mechanism. This mechanism is common to all MT fuzes and con-sists of the timing disc, a setting pin, a spring ham-mer assembly, and the main spindle. The timing disc has a firing notch on one side and a forked set-ting lug on the other side. This lug engages the set-ting pin located in a shoulder inside the lower cap. The timing disc is secured to the central drive shaft by a Belleville spring, or friction clutch, so that it may be turned independently of the main spindle.

Around the timing disc is a retaining ring that pre-vents the timing disc from riding forward when the projectile is rammed home in the gun. The ring also prevents the hammer from driving the setting lug too far aft. Aft of the timing disc is a safety disc, the projection of which bears against the elbow piece of the firing arm. This safety disc is rigidly secured to the main spindle so that it will rotate out of the way only when the clock operates. Its purpose is to provide a safe and minimum set-ting below which the fuze will not function. In set-ting the clock, the lower cap is rotated, which rotates the timing disc to the desired position, because the setting pin in the lower cap is engaged by the setting lug of the timing disc. Disengage-ment of these two parts is effected by the spring hammer assembly at setback during gun launch.

Figure 4-12 Typical Mechanical Time Fuze Timing Mechanism (Early Version), Schematic View

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4-3.3.4.2. Clock Mechanism. In MT-only fuzes, this system consists of two centrifugal drive gears, a series of reduction gears, and the escapement mechanism. The centrifugal gears engage a gear on the main spindle and are weighted on one side so that they will turn under the impetus of centrifugal force and rotate the main spindle. The centrifugal gears have kickoff springs to ensure their starting. Springs are necessary in large projectiles that have relatively less rotational velocity and thus less centrifugal force acting on the fuze. The springs will power the clock mechanism for about one third of its maximum run without the assistance of centrifugal force working through the centrifugal gears. In MT/PD fuzes, the centrifugal gears are replaced by a clock mainspring.

In both types, the reduction gears are con-nected to the main spindle; the speed of their rota-tion is controlled by the escapement mechanism connected to the final gear in the train. The escapement mechanism consists of an escapement gear, escapement lever, escapement spring, and a lock on the escapement lever. Depending on the timer, the lock will be either a safety lever plate and safety lever detent and spring or a sliding pallet and spring assembly. In the assembled position, the escapement lever is prevented from moving by the lock. The lock is removed by centrifugal force. The escapement lever acts as a balance wheel and is caused to move back and forth by the escape-ment spring. This is a straight-wire hairspring secured and adjusted for length (timer beat rate) at both ends by adjusting blocks and attached at its center to the escapement lever.

4-3.3.4.3. Firing Mechanism. This system con-sists of the firing arm, the firing arm shaft, the set-back pin, the safety block, the firing pin safety plate, and the firing pin. MT/PD fuzes do not have a setback pin or the safety block on the firing pin. On one end of the pivoted firing arm is a weight; on the other is an elbow piece that bears against the outer periphery of the timing disc. The firing arm shaft, is rigidly secured to the firing arm. This shaft, in some fuzes, has a spring to assist the weight on the firing arm in turning the shaft. The firing arm shaft, which is keyed to the setback pin

by another pin, is prevented from turning by the setback pin, which is held in position by the set-back pin spring. The pin rests in front of a projec-tion on the firing arm shaft. On some MT-only fuzes, a firing pm safety block is substituted for the setback pin, and on other fuzes, both are used. This safety block is held by a spring against a shoulder on the firing pin, preventing the firing pin from moving toward the primer. Centrifugal force moves the safety block against its spring to free the firing pin. On the after end of the firing arm shaft is a notch. The firing pin safety plate bears against the firing arm shaft in such a position that the plate will pass through the notch when the shaft is rotated. The pivoted safety plate is fitted under a shoulder of the cocked firing pin, holding the firing pin away from the primer.

4-3.4. Explosive Component (Magazine). MT-only fuzes have a magazine charge of black pow-der. The 5-inch, 54 caliber MT/PD fuzes have a CH-6 booster. The MT fuze black powder charge is strong enough to initiate the expelling charge in chemical, illuminating, or chaff projectiles, but is used with an AD fuze to provide additional safety on these rounds and to provide an extra explosive boost on HE rounds.

4-3.5. Safety Features. In MT-only fuzes, a spring-loaded safety lever prevents oscillation of the escapement until centrifugal force takes effect. The safety lever, in turn, is immobilized by a spring-retained detent prior to the onset of centrifu-gal force. When either the MT or MT/PD fuze is set on SAFE (or PD) or a setting involving a delay shorter than the prescribed minimum delay, the fir-ing slot in the timing disc is covered by a safety disc. The safety disc prevents the timing disc from releasing the firing arm when in these positions. The timing disc is prevented from rotating by the setting pin in the lower cap, which is disengaged only by a strong setback force. The firing pin can-not move toward the primer until the firing pin safety plate or safety block and/or the setback pin (depending on the particular fuze) is disengaged from the firing pin. The safety plate and block requires the action of centrifugal force; the setback pin requires the impetus of sharp acceleration.

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4-3.6. Operation. The fuze is set by rotating the lower cap to position the correct number of sec-onds over the scribe mark on the exterior body. The setting pin, inside the lower cap, rotates the setting lug on the timing disc. When the projectile is fired from the gun, the force of setback accom-plishes the following:

a. The hammers are driven aft against their spring mountings to strike the setting lug, bending the soft metal of the setting lug and freeing it from the setting pin. When the force of creep takes effect, the springs return the hammers to their for-mer position forward.

b. The setback pin in the timer, if one is pres-ent, overcomes its spring and drops into the aft por-tion of the fuze. This action frees the firing arm shaft for later rotation.

c. The setback pin in the S&A of the 5-inch, 54 caliber MT/PD fuze drops into the lead block, freeing the rotor.

As the projectile rotates, centrifugal force accomplishes the following action:

a. If a firing pin safety block is present, it is moved outward and clear of the firing pin.

b. In the MT-only fuzes, the safety lever detent is moved outward against its spring, disen-gaging it from the safety lever plate. The lever plate is then pivoted out of the way, releasing the escapement lever. The movement of the safety lever plate furnishes sufficient impetus to start the oscillation of the escapement lever against its spring. In the MT/PD fuzes, the two pallet locks on the escapement lever move outward and release the escapement lever.

c. In the 54-inch, 54 caliber MT/PD fuze S&A, the spin detents move outward and release the rotor.

d. In the MT-only fuzes, as soon as the escapement mechanism has been unlocked, the weights on the centrifugal gears move outward. In turning, they rotate the main spindle and the timing disc. In MT/PD fuzes, the mainspring pulses outward, driving the main spindle and the timing disc. The speed of this rotation is controlled by the reduction gears and the escapement mechanism.

The rotation of the timing disc continues until the firing notch is presented to the elbow piece of the firing arm.

e. As soon as the 5-inch, 54 caliber MT/PD fuze S&A rotor has been unlocked, it drives to the armed position.

f. When the firing notch is in front of the elbow, the weight on the opposite end of the firing arm pushes (because of centrifugal force) the elbow into the notch, thereby rotating the firing arm shaft. In some fuzes this action is assisted by a spring.

g. As the firing arm shaft rotates, the notch in its aft end is presented to the firing safety plate. The safety plate pivots through this notch, thus moving free of the shoulder on the firing pin. The firing pin is then driven into the primer or detona-tor by its compressed spring. In the MT only fuzes, the primer ignites the relay charge and in turn the magazine charge. In the 5-inch, 54 caliber version, the relay initiates the detonator in the S&A rotor, which in turn initiates the lead and booster charges.

4-3.7. Fuze MK 342 (5” Mechanical Time).

4-3.7.1. General. The MK 342 MOD 0 MT fuze (Figure 4-13) is essentially a combination of the MK 25 MODs 4 and 5. Fuze MK 342 retains the same external characteristics as well as the same setback pin design used in the MK 25 MOD 5. In comparison to the MK 25 MOD 4, the MK 342 is identical in that it retains the same cen-trifugal gear weights, drive spring, and safety block and has the same moistureproofing features, using thread sealant and varnish to seal the upper cap and bottom closing plug. MOD 1 is similar to and interchangeable with the MOD 0 fuze. Modifica-tions to improve the reliability of the MOD 0 pre-mature trap include changes in the timing disc assembly, zero adjusting plate, firing arm, and fir-ing arm spring. To improve setting torque stability, a six-wave beryllium copper torque spring has been installed.

4-3.7.2. Operation and Safety Features. The operational design and safety features of the MK 342 are similar to those of the MK 349 MOD 0 with the primary difference being the improved premature trap, fail-safe feature. Addi-tional safety is assured because this fuze is used

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with the MK 39 AD fuze, which contains an out-of-line explosive train that provides a safe separa-tion of over 383 feet from the gun.

4-3.7.3. Firing Time Characteristics. The MK 342 functions approximately within plus or minus 1 percent of the set time.

NOTEReports of malfunctions shall classify bursts occurring within 2,000 feet as close aboard prematures. Those occur-ring beyond 2,000 feet shall he classified as early bursts.

4-3.7.4. Moistureproofing. The MK 342 fuze has a moistureproof design intended to give longer life and greater reliability. The moistureproofing is accomplished as follows:

a. MK 342 contains an internal desiccator unit of silica gel in the base cavity of the fuze body. This silica gel absorbs and retains all moisture in the air trapped in the fuze at assembly, thus pre-venting rusting of steel parts or deterioration of explosive components.

b. The joint between the upper and lower caps is coated externally with thread sealant and varnish. This film of varnish is practically imper-vious to moisture, hence, serves as a mechanical barrier to its passage.

c. The primer screw assembly is moisture-proofed by inserting a Vinylite disc under the black powder relay pellet and by coating both ends of the primer screw assembly with varnish.

d. Thread sealant is applied to the joint between the body and the bottom closing screw. The sealant serves to exclude moisture and keeps the joint mechanically tight. The brass disc at the center of the bottom closing screw is crimped in under a washer, then coated with varnish.

4-3.7.5. Use.5-inch, ILLUM, Puff-MT

projectiles (full and reduced charges)


Specification..................................WS 13528Drawing............................................2511237Weight

MOD 0.................................... 1.41 pounds MOD 1 .................................... 1.45 pounds

Length ....................................... 4.581 inches Thread size ..............................1.700-14NS-1

4-3.7.7. Explosive Components.Primer (percussion cap) ................Either FA 70

primer mix consisting of potassium chlo-rate, antimony sulfide, TNT, and lead sul-focyanate; FA 70 primer mix with 8 percent ground glass; or Winchester 529 Primer Mix, 28.5 milligrams

Booster ....................................... Black powder

4-3.7.8. Arming.No arm .................. 33.3 revolutions per secondArm ........................ 100 revolutions per second

4-3.7.9. Function.Type ................................................MechanicalDelay...................................0.8 to 45.0 seconds

Figure 4-13 Fuze MK 342 MOD 0 (Mechanical Time), External View

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4-3.8. Fuze MK 393 MOD 0 (5” Mechanical Time/Point Detonating).

4-3.8.1. General. The MK 393 MOD 0 MT/PD fuze is shown in Figure 4-14. The MK 393 MOD 0 provides a settable function time with a point deto-nating backup and selectable point detonation, for use in the MK 41 HIFRAG and MK 64 projectiles.The fuze has a settable timing capability ranging from 3 to 95 seconds. The timer is accurate to approximately plus or minus 5 percent of the set time, which is less accurate than the MK 342 fuze

because of the longer time setting range. The point detonating feature is sensitive against light targets and earth and water impacts. The MK 393 MOD 0 fuze contains a MK 41 safety device with fuze arming delay time of over 360 feet that is compara-ble to the safety device of the MK 395 AD fuze. The clock mechanism consists of a coil spring driven movement assembly and the MK 342 timing disc. It contains a pin located inside the fuze body, that prevents the S&A/lead block assembly from insertion past the pin the fuze body, if the fuze rotor is in the armed position at final fuze assem-

Figure 4-14 Fuze MK 393 MOD 0 (Mechanical Time/Point Detonating), Cross-Sectional View

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bly. Recent production MK 393 fuzes have an improved torque joint construction, similar to that of the MK 342 fuze, to correct a setting problem caused by excessively high slip torque.

4-3.8.2. Use.5-inch, HE, HI-FRAG, TP-Puff projectiles

4-3.8.3. Physical Characteristics.MOD 0 Specification ................................. WS 13929

Drawing ........................................... 2512434 Weight1.42 pounds Length ........................................5.985 inches Thread size...............................2.0-12UN-2A Intrusion depth ................... 2.21 inches, max.

4-3.8.4. Explosive Components.Stab primer ....... WOX-87A; NOL 130, FA 879Stab detonator.........MK 44 MOD 1; NOL 130,

lead azide, tetrylRelay detonator ............. WOX-80A; lead azideDASD.....................................................MK 41 Rotor detonator .................... MK 23 MOD 1;

NOL 130, lead azide, tetryl Lead ....................... Two MK 8, charge CH-6Booster assembly Dwg 2512435.............. CH-6

4-3.8.5. Arming.No arm......................50 revolutions per secondArm...........................75 revolutions per second

4-3.8.6. Function.Type.......................................................MT/PDDelay ........................................ 3 to 95 seconds

4-3.8.7. Packing.576/pallet; 30.2 cubic feet

4-4. ELECTRONIC TIME (ET) FUZES

4-4.1. MK 432 Electronic Time Fuze. The MK 432 provides the KE-ET and HE-ET rounds with an accurate timed burst to effectively distrib-ute the payload at all ranges. The fuze is an induc-tively set, electronic time (ET) projectile fuze. It is

a Naval version of the U.S. Army M762A1 ET fuze without the hand setting option or the PD fea-ture. It is designed to be used with the MK 45 MODs 1, 2, and 4 Naval Gun Mounts. Just prior to gun firing, the MK 34 Electronic Fuze Setter inductively sets the time through the maglink assembly in the nose of the fuze. The fuze duds if not properly set or fails to function in the electronic time mode. The MK 432 is intended for all cargo-type rounds (e.g., illuminating, smoke, white phos-phorus, and submunition.) The MK 432 meets the (NATO) contour requirements of the MIL-STD-333 and STANAG 2916. In the ET mode, the Gun Weapon System (GWS) sets the fuze from 0.50 to 327.66 seconds in 10 millisecond increments.

4-4.2. Use.5 inch projectiles

4-4.3. Physical Description.MOD 0

Specification..................................WS33602Drawing.......................................... 7344550Weight ......................................... 1.1 poundsLength .........................................5.27 inchesThread Size ...................... 2.0 - 12 UNS - 1A

4-4.4. Explosive Components.Piston Actuator

DWG 12550906 ...................... PA535 (8 mg)Detonator, Electric

DWG 12550926 ..................... PA539 (30mg)Primer Battery

PA536 ..........................NOL130 (20mg) lead styphnate (spot)

Lead, DWG 12550963 ........ PA534 (168 mg)

4-4.5. Arming.

4-4.5.1. First Safety (Set Back). 800 g No Arm1000 g All Arm

4-4.5.2. Second Safety (Spin).15 rps .................................................. No Arm35 rps .................................................. All Arm

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4-4.5.3. Arming Time.450 msec Minimum

4-4.5.4. Arming Distance.1000 ft Minimum for 5-in projectile with a

Service Propellant Charge

4-4.5.5. Function.Type...................................................ElectronicDelay .............Arming occurs 50 ms Before Set

Function Time

4-5. PROXIMITY FUZES

4-5.1. MK 417, MK 418, MK 73 (Variable Time-Radio Frequency (VT-RF) Fuzes).

4-5.1.1. Background. The MK 73 fuze is an active radio-frequency proximity fuzes used in the nose of 5"/54 high explosive-loaded, fragmenting projectiles. The MK 417 is a short intrusion ver-sion of the MK 72 MOD 17 solid-state proximity fuze for 76mm projectiles. The MK 418 fuze is a short intrusion version of the MK 73 MOD 13 fuze for 5"/54 projectiles. See Figure C-20. The earli-est MODs of the MK 70 series fuzes were first pro-duced in 1947. VT-RF fuzes are used in several applications such as antiaircraft defense, shore bombardment and ship topside damage. The anti-aircraft role requires that the fuzed projectiles be fired at all gun azimuths and quadrant elevations (QE) necessary to track and destroy the target. When ship task-forces stayed in close proximity to each other for protection, it was obvious that fuzed rounds which did not come close enough to a target to be triggered could eventually fall on other ships in the task force and become a hazard. The even-numbered MODs, therefore, contain a self-destruct (SD) reed spin switch that operates on centrifugal force generated by projectile spin but most of these fuzes are out of service. Spin decreases gradually as range increases and eventually the SD switch recloses at some range beyond the maximum range of antiaircraft effectiveness. The closing of the switch detonates the round. Shore bombardment and ship topside damage operations generally take place at much greater ranges and with predeter-mined control over the azimuth and QE. There-fore, no SD capability is needed and the odd-numbered MODs are used. For the above reasons,

whenever a change was made to the fuze design which necessitated a MOD change, a pair of MODs was released with the only difference being the inclusion of the SD switch in the even num-bered MOD. Only non-SD projectiles are being procured. However, the supply of SD-type projec-tiles should be used until exhausted.

4-5.1.2. Design Changes. During the years 1947 through 1958, most design changes were a type which extended shelf life of the various com-ponents, increased reliability, or improved minia-turization. Safety has always been excellent in the handling and use of proximity fuzes. Some of the changes resulted in more compact reserve energiz-ers (RE), eliminated mercury (primer unshorter) switches, added clock-type rear fitting safety devices (RFSD) to improve arming time accuracy, moved the “upstairs” location for the oscillator tube to a “downstairs” location to minimize rain-drop generated microphonics, increased oscillator frequency ranges to improve electronic counter-measure (ECM) protection, and reduced the size of the miniature vacuum tubes. The electronic cir-cuits changed very little; the passband and sensitiv-ity remained the same. By 1958, a new battery chemistry system using lead-lead dioxide cells and fluoroboric acid electrolyte was available. For the same volume, more power and a wider temperature range with lower output impedance resulted. A high power version of the MK 73 fuze was released. Two additional changes were made. The MK 18 RFSD and a companion MK 30 booster assembly were designed and incorporated. The new RE was put into the MK 73 MODs 4 and 5 in 1960 along with the MK 18 RFSD and the MK 30 Booster Assembly. No other significant electronic changes were made to the fuzes until 1973 (although evolutionary changes were made to the RFSD and booster). Then solid-state electronic versions, MK 73 MODs 12 and 13 fuzes, were released to production. The MK 417 MOD 0 fuze is a short intrusion version of the MK 72 MOD 17 fuze with a similar, but improved circuitry. The amplifier and reserve energizer cans were short-ened and the spacer block was eliminated. The MK 418 MOD 0 fuze is a short intrusion version of the MK 73 MOD 13 fuze. It has the same ampli-fier package as the MK 417 MOD 0 fuze, but uses a different oscillator frequency range.

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4-5.1.3. Design Features. The current VT-RF fuze can be used as a general purpose fuze in a variety of applications. It has high reliability, good ECM resistance, semi-adaptive burst positioning and provides good burst positions with a reduced burst radius low over the waves.

4-5.1.4. Physical Description. All MK 70-series and MK 417/418 fuzes function fundamen-tally alike and contain the same basic compo-nents. The MK 417/418 fuzes differ from the MK 70-series in that they have a standardized ABCA ogive and intrusion. Fuze profiles, thread intrusion lengths and weights differ because of pro-jectile design differences.

4-5.1.4.1. Front Case. The front case for all VT-RF fuzes consists of two pieces. One piece is a threaded steel insert with a cadmium or zinc chro-mate coating for rustproofing. The other piece is a plastic radome material called a nose piece. The solid-state MODs of the MK 70-series fuzes and the MK 417/418 fuzes use polyphenylene oxide (PPO). All the older MODs containing vacuum tubes use polytetrafluorethylene (teflon). PPO is advantageous because it is cheaper and generates fewer microphonics when struck by rain drops dur-ing flight. Teflon radomes are color-coded green for non-SD MODs and white for SD MODs. The PPO radomes are color-coded green for the MK 418 Fuze and beige for the MK 417 Fuze. Since these fuzes no longer use an SD switch, the colors are used to distinguish between the two fuzes.

NOTESince the MK 417 and MK 418 fuzes essentially have the same physical dimensions, extreme care must be used to prevent assembly of either fuze into the wrong projectile. Safety will not be com-promised, but the fuze will not correctly operate electronically.

4-5.1.4.2. Sleeve. The steel sleeve encloses the fuze components and screws into the front case. It is protected from corrosion by a thin coating of either cadmium or zinc chromate. The strength of the sleeve is sufficient to support the weight of all the components during periods of extremely high setback forces encountered during projectile firing.

The sleeves used with all later MODs of the MK 70-series fuzes and the MK 417/418 fuzes contain a brazed-in diaphragm. See Table 4-1through Table 4-2 for information about the MODs having the diaphragm. Assembly of the fuze com-ponents is different for sleeves with and without diaphragms.

4-5.1.4.3. Monitor. The monitor contains all the electronic subcomponents of the fuze. The resis-tors (R), capacitors (C), tubes, transistors, inte-grated circuits (IC), and other components of the signal processor are housed in a metal amplifier (shield) can and the impact switch and oscillator components are mounted on top of the can. All fuze MODs which have vacuum tube circuits have the electronic components placed in a polyethylene receptacle which provides proper shock support and electrical insulation. Components are electri-cally wired at the top and bottom of the receptacle with leads brought out the bottom for soldering into the baseplate pins. Fuzes with solid-state elec-tronic components have the components mounted on two printed circuit (PC) boards. The boards are supported on the baseplate and properly spaced with heavy wire leads which also provide the elec-trical circuit connections between the baseplate pins and the boards. Beyond this stage, all fuzes are assembled into the shield can the same way.

4-5.1.4.4. Reserve Energizer. The reserve energizer (RE) is a dry-charged battery contained in a steel can which plugs into the base of the mon-itor. It supplies the electrical power for the fuze circuitry. It also contains through leads to provide electrical connections for the firing pulse, the reed spin switch and the RFSD ground. The battery consists of a stack of plated electrodes with appro-priate insulators and spaces between each plate. The center of the stack is open to accept a glass ampule containing liquid electrolyte. Setback and projectile spin forces cause the glass to shatter and then fill the spaces between the plate with the elec-trolyte. The battery is potted with plastic material before being placed in its can. The can is crimped over the RE baseplate to hold the assembly together.

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Table 4-1 VT-RF Fuzes MK 417 and MK 418, Characteristics

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Table 4-2 VT-RF Fuze MK 73, Characteristics

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4-5.1.4.5. Spacer Block. The spacer block is a molded plastic cylinder with most of its center hol-lowed out. The top surface is thick enough to provide support for the RE base plate. The hollow section reduces the weight of the spacer block on the RFSD and at the same time distributes the RE setback load to the outer wall of the RFSD which is better suited to support it. The height of the spacer varies from fuze to fuze. Some fuzes do not need a spacer at all. Float-ing pins provide electrical connections through the spacer between the base of the RE and the RFSD.

4-5.1.4.6. Rear Fitting Safety Device. The rear fitting safety device (RFSD) shown in Figure 4-15 consists of laminated metallic disc sections that contain a cover with a mal-assembly pin, a clock assembly, a rotor assembly, an electric deto-nator, a relay detonator, and a booster lead. Some MODs include a self-destroying device. These subassemblies are described separately in the fol-lowing paragraphs.

4-5.1.4.6.1. Clock Assembly. The clock assem-bly consists of a spin-operated sector gear with helper starting spring, an escapement mechanism that regulates the rotational speed of the sector gear, two detents, a setback pin, a rocker pin, and a spring. The clock assembly provides a time delay before releasing the rotor. Operation of the clock assembly is as follows: Setback force caused by gun firing moves the setback pin back against the rocker pin and spring, freeing the sector gear. The rocker pin allows the setback pin to cant due to centrifugal force and lock behind a shoulder. Cen-trifugal force caused by projectile spin also releases the two springloaded detents to free the escapement mechanism. Centrifugal force acting on the sector gear drives the time regulating escapement mechanism. After a time delay of 0.23 to 0.58 second, the sector gear cam rotates to a position that releases the rotor.

Figure 4-15 Rear Fitting Safety Device

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4-5.1.4.6.2. Rotor Assembly. The rotor is a metallic disc containing an out-of-line section of the explosive train and a pin for breaking the deto-nator shorting wire. It is pivoted off balance so that projectile spin force develops a torque tending to align the out-of-line section of the explosive train. However, a sector gear cam, controlled by the clock assembly, prevents rotation until the clock operates for the preset time period. An additional interlock is imposed by two slider-type detents located in a radial slot in the rotor and extends across to an aligned slot in the rotor housing. The two detents interlock each other at the rim of the rotor that is also at the projectile spin axis. This outer detent is held in place by an omega-shaped spring. Centrifugal force causes separation of the detents in opposite directions and removes the interlock. This completes the arming of the rear fitting safety device. If the projectile is dropped, both detents are free to slide together in one direc-tion, but they cannot separate to remove the inter-lock.

4-5.1.4.6.3. Electric Detonator. The electric detonator consists of a small cylindrical cup of explosive with a carbon or wire bridge attached to electric leads. When a surge of electric current passes through it, the bridge is heated to a high temperature and ignites the explosive.

4-5.1.4.6.4. Relay Detonator. The relay detona-tor consists of a small container of explosive and serves as an intermediate detonating explosive unit between the detonator and the booster lead-in.

4-5.1.4.6.5. Booster Lead-ln. The booster lead-in is a secondary detonating explosive that ampli-fies the output of the primary explosives in the safety and arming device and reliably initiates the booster.

4-5.1.4.6.6. Reed Spin Switch. The purpose of the reed spin switch is to act as a self-destruct fea-ture. Undetonated projectiles are exploded at a pre determined point before end of flight in order to protect friendly troops and ships. The switch is so adjusted that, if the projectile is not detonated by an air target, the switch closes when the spin drops to a predetermined value. This causes self-destruc-tion of the unit by closing the circuit and discharg-

ing the firing capacitor through the detonator. Although the switch is normally closed, it is opened quickly by the angular acceleration of the projectile, which attains its maximum near the muzzle of the gun. The spin of a projectile decreases with increasing time of flight, and hence may be used for closing the switch at a predeter-mined distance from the gun. This self-destruct feature is present in odd numbered fuze MODs. It is absent in even-numbered MODs to permit impact VT functioning on surface targets. Fuzes produced since 1971 do not have the reed spin switch (no self-destruct feature), and provisions for it have been removed from the current RFSD MK 42 MOD 3. The reed spin switch is electri-cally connected across the firing capacitor. The reed spin switch, shown in Figure 4-16, consists of a metal cup with an adjustable contact stud threaded through the lower side and a metal reed inserted through an insulator in the top of the cup. The reed serves as one terminal of the switch and the adjustment contact stud serves as the other ter-minal. The spring action of the metal reed holds it in contact with the stud, forming a closed circuit. The switch is mounted off center in the fuze so that when the projectile is fired, centrifugal force over-comes the spring tension of the reed, causing it to separate from the contact stud, thus breaking the short circuit across the firing capacitor immedi-ately upon firing. The inside of the case is insu-lated with a plastic tube so that the reed will not short against the case.

4-5.1.4.7. Booster. Fuzes manufactured after 1956 have the AD fuze replaced by a booster. The booster is a high-explosive filled unit usually encased in a thin metal cup that is threaded and assembled to the fuze. Its principal function is to amplify the explosive train’s detonation shock to the main charge of the projectile.

4-5.1.5. Assembly and Waterproofing. Assembly and waterproofing are accomplished as follows:

a. The base of the oscillator-amplifier unit is plugged into the reserve energizer that in turn plugs into the top of the rear fitting. In some fuzes a spacer block is assembled between the reserve energizer and the rear fitting. This subcomponent assembly is inserted into the upper end of the metal

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sleeve. The RFSD rests on a shoulder inside the sleeve. A diaphragm, brazed or welded in the sleeve, is located below the bottom of the RFSD next to the booster. Stack spacers are used as nec-essary to meet the subcomponent height require-ment for the capsule assembly. Stack pressure is applied, and the assembly is secured by crimping the lip of the sleeve onto the amplifier flange to form the capsule assembly. This assembly is then screwed into the front case and tightened to a spec-ified torque. The booster assembly is screwed into the back of the sleeve and torqued.

b. Waterproofing of this assembly is depen-dent upon the gasket seal between the front case threaded insert shoulder and the upper edge of the crimped sleeve, as well as the diaphragm seal between the RFSD and the booster. Additional

sealing is provided by sealant on the booster cup threads and a lead gasket in the crimp between the amplifier assembly and sleeve.

c. Earlier of VT-RF fuzes have a sleeve with-out a diaphragm; thus, the fuze subcomponent assembly is handled differently. The subcompo-nents are assembled in the same order as the later, except they are placed into the front case first. The sleeve is placed over the assembled subcompo-nents and screwed into the front case with the spec-ified torque. Stack pressure is applied to the bottom of the RFSD, and a holding ring is tight-ened. The booster assembly (or auxiliary detona-tor) is screwed into the inner thread of the holding ring. A waterproofing gasket and another holding ring are placed around the booster (or auxiliary det-onator) and tightened with the required torque. Thus waterproofing at the lower end of the sleeve is accomplished by means of the waterproofing gasket sandwiched between two thin metal washers and held in compression between the fuze sleeve and the lower part of the booster or auxiliary deto-nating fuze by the threaded holding ring. The interface between the sleeve and front case is waterproofed the same as in the later fuzes.

4-5.1.6. Operation. VT-RF fuzes are activated by combined proximity, rate of approach, and angle of approach to targets that provide the proper reflection. These include substances such as metal, water, and earth. Operation is the same day or night. Detonation of the main charge in the projec-tile is accomplished by the following sequence of events. The VT-RF fuze transmits a continuous radio frequency signal that is reflected by the tar-get. When the reflected signal, combined with the transmitted signal, attains the proper strength, the fuze discharges a charged capacitor through an electric detonator. The initiation of the detonator explodes a relay detonator, a lead, and a booster, which then detonates the main charge of the pro-jectile. Unlike the time fuze, no time setting is nec-essary or possible with the VT-RF fuze. Detonation occurs automatically when the projec-tile is sufficiently close to the target. Figure 4-17shows the sequence of events in the operation of individual fuze components.

Figure 4-16 Reed Spin Switch, External and Cross Sectional Views

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4-5.1.6.1. Fuze Safety. When the projectile is loaded for firing, the fuze is in the safe condition. In this condition, the ampule in the reserve ener-gizer is unbroken, and the energizer does not sup-ply energy to the electric circuits of the fuze. The reed spin switch, when present, is closed, thus placing a short circuit across the firing capacitor. The RFSD clock cannot operate because of a set-back pin and spin detents that mechanically lock it, and the shorting wire prevents the electric detona-tor from being fired.

4-5.1.6.2. Fuze Activation. When the projec-tile is fired, the ampule in the reserve energizer is shattered on the breaker as a result of setback forces, and the electrolyte is released. Centrifugal force distributes the electrolyte to the battery cells, and the battery becomes active. Centrifugal force causes the reed spin switch, when present, to open

immediately upon firing, removing the short circuit from the firing capacitor. Setback force unlocks the rear fitting setback pin on the clock, and centrifu-gal force releases two detents holding the clock mechanism and rotates the cam shaft to the rotor release position, which in turn, breaks the safety wire. A short minimum time is required for this action.

4-5.1.6.2.1. Clock Mechanism. The clock mechanism remains in an unarmed position until setback forces remove a setback pin from its posi-tion in front of the sector gear. After the setback pin is removed, centrifugal force operates the detent levers and permits the clock mechanism to operate. The force of a helper spring behind the sector gear aids the centrifugal force to initiate the clock mechanism. Once the operation of the clock

Figure 4-17 Operational Sequence of Variable Time-Radio Frequency Fuze Components when Fired from a Gun

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mechanism is initiated, centrifugal forces continue to act upon the sector gear until it has rotated fully to unlock the explosive train’s rotor.

4-5.1.6.2.2. Explosive Train Alignment and Electrical Arming. At this time, the rotor, carry-ing an out-of-line detonator, turns to permit align-ment of the explosive train under the impetus of centrifugal force. The turning of the rotor to the armed position breaks a shorting wire across the electric detonator leads to complete the arming of the RFSD. After the energizer is activated, it becomes a source of power for the electrical part of the fuze; the firing capacitor begins to receive a charge, and the transmitter starts to radiate a radio signal.

4-5.1.6.3. Armed Flight. The fuze is fully armed when the safety wire is broken and the firing capacitor is charged and, when present, the AD fuze is armed. For most gun projectiles covered in this manual, the arming distance varies from 700 to 1,550 feet, depending on projectile caliber. The radio signals radiated by the fuze are reflected from targets such as metal objects, water, and earth. The engine and control cables of nonmetallic aircraft also reflect signals. When the projectile comes into close proximity to the target, the reflected sig-nal from the target reaches the required amplitude and causes the thyratron or silicon-controlled recti-fier to discharge the firing capacitor through the detonator. The blast from the detonator initiates the relay detonator, which in turn, initiates the AD fuze or booster. The AD fuze or booster detonates the main charge in the projectile.

4-5.1.6.4. Self-Destruction. Where the fuze is provided with the self-destruction feature and the projectile is not detonated before the self-destruc-tion range is reached, the decrease in the spin of the projectile will close the reed spin switch. This closure causes self-destruction of the projectile by closing a circuit and discharging the firing capaci-tor through the detonator.

4-5.1.7. Safety Features. VT-RF fuzes are among the safest fuzes in the U.S. Navy. Many design features are provided to ensure safe han-dling, safety in the bore, and freedom from muzzle bursts. Rough handling may cause damage, result-

ing in abnormal operation or duds, but it is improb-able that such treatment will be hazardous. A severe blow to the fuze (such as dropping the fuzed projectile) will not reduce safety but may decrease operability and may even render the fuze a dud if the battery ampule is shattered. If dropping occurs within 1 minute before loading into the gun and fir-ing, the round has a high probability of operating normally. After 1 minute the round is still safe to fire, but reliability will degrade rapidly with time because of the short battery life after activation. Components contributing to safety of the VT-RF fuze are the reserve energizer, the charging resistor, two spin detents, the setback pin, the mal-assembly pin, the clock unshorting wire, the out-of-line rotor, and, when used, the reed spin switch. The features of these components have been described in the preceding paragraphs.

4-5.1.8. Functional Description and Theory of Operation. This section is primarily for personnel who have some knowledge of RF circuitry and/or who seek a more detailed explanation of the theory of operation of VT-RF fuzes. The process is described by which each component performs its task and how these tasks combine to perform as a fuze.

4-5.1.8.1. Design Considerations. The design of an active VT-RF (proximity) fuze circuit is determined primarily by considerations of the echo area of the intended targets, the closing velocity between the fuze and target, the limitations imposed by electronic circuit components, clutter from unwanted or nearby targets, background sources of radiation, and environmental con-straints.

4-5.1.8.2. Target Energy Considerations. Fragmenting projectiles are capable of inflicting damage to a variety of moving and stationary tar-gets such as aircraft, missiles, ship topsides, radar sites, and personnel. Proximity fuzes of the RF type are designed to detect the presence of a nearby target by transmitting a high frequency signal in the direction of the target and detecting the small amount of RF energy reflected from it.

4-5.1.8.2.1. Air Targets. Aircraft and missiles have small radar cross sections (RCS) measuring from less than a square meter to several square

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meters. They generally fly at speeds in excess of MACH 0.5. This requires fuze circuits which are very high in sensitivity and tuned to operate at high Doppler frequencies. More sensitive circuits are possible only if the RE has sufficient power capac-ity to allow the fuze to radiate more power and thus obtain a better signal to noise (S/N) ratio. The cir-cuits and components also have to be designed to minimize internal noise sources.

4-5.1.8.2.2. Surface Targets. Targets on the water or ground surface may have RCS’s which vary from a very small value (personnel) to a very large value (large ships). However, they have one item which is common, the surface they are on always has a very large RCS. Hence proximity fuzes fired at surface targets generally depend on the energy reflected from the surface to provide the proper height of burst (HOB) in the presence of the actual target. Velocities of surface targets are gen-erally considered insignificant compared to the projectiles velocity and require the fuze to operate at lower Doppler frequencies than for the air tar-gets. In the case of large surface targets, such as ships, the superstructure may extend sufficiently above the surface and have a large RCS which will provide a return signal sufficient to trigger the fuze. Ship superstructures are quite vulnerable to the small fragments of an exploding shell.

4-5.1.8.3. Background Energy Consider-ations. The most frequently encountered and gen-erally the largest source of unwanted background energy is the signal to the fuze from a water or land surface when the target is a small missile or aircraft close to the surface. Thus it is necessary to dis-criminate between the target and surface return sig-nal. A variety of techniques have been used but none has completely solved the problem of provid-ing adequate discrimination. Other unwanted energy is radiated from both friendly and other transmitters, such as radars, navigational equip-ment, radio and television stations, jammers, and communication links. Again, designs must either avoid operating on the same wavelength or find ways of countering the source. Environmental conditions also impose stringent design require-ments on the fuze. All parts of the fuze must be capable of being stored for long periods of time between the temperatures of -40°F and +160°F and remain operable between the usage temperatures of

-20°F and +130°F. Rain drops striking the fuze radome during flight must not generate micro-phonic noise sufficient to prefunction the fuze. Passage through clouds, where static charges and lightning exists, must not cause the fuze to pre-function or be damaged. Last, but not least, all fuzes must be safe to handle and use in the pres-ence of radiation from shipboard and dockside electronic equipment (RADHAZ safe).

4-5.1.8.4. Circuit Design. Figure 4-18 is a block diagram of the solid-state VT-RF fuze. Tube-type fuzes are similar except they do not have a separate detector or noise filter circuit. All fuzes in the MK 70-series, regardless of MOD, and the MK 417/418 fuze are similar in their design and perform to the same theory of operation. In general, the fuze transmits an RF signal and detects the small target return signal. This small signal is amplified, filtered, rectified, integrated and compared to a firing threshold and generates a firing pulse to the electric detonator. Because the projectile body is depended on to act as one half of an asymmetric dipole, the operating frequency of each Mark number fuze is different in order to accommodate the variation in projectile bodies. Other small variations exist between the MKs and MODs because of differences between and avail-ability of electronic components at the time of design, for example, combined versus separate oscillator-detector circuits; different amplifier bandpass frequencies; variations in the applications of the automatic gain control (AGC) circuitry to minimize wave noise, RE noise and microphonics; no electronic RE noise filtering in older MODs; and solid state circuitry instead of vacuum tubes in the new MODs.

4-5.1.8.5. Transmitter-Receiver. The antenna, oscillator, detector and noise filter blocks shown in Figure 4-18 contain the circuit components which perform the transmit-receive function of the fuze. The antenna is an asymmetrical dipole. The antenna top hat forms the foreshortened, or asym-metrical half of the dipole. The projectile body, including its threaded steel insert, forms the other half. The radiation pattern has the same shape as a conventional dipole, but the impedance is several orders of magnitude higher. Figure 4-19 is a cross section view of a typical electric field radiation pat-tern of a fuzed projectile.

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Figure 4-18 Solid-State VT-RF Fuze Block Diagram

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4-5.1.8.5.1. Transmitter. The transmitter is formed by coupling the oscillator to the antenna. The oscillator consists of an active electronic component such as a transistor or vacuum tube and several passive components such as capacitors, resistors, chokes and coils wired into a Hartley or a Colpitts oscillator circuit. The oscillator is designed and adjusted to operate in a controlled state of instability which allows it to react and change frequency upon receiving a return signal from a nearby target.

4-5.1.8.5.2. Receiver. The antenna and trans-mitter, along with one or more additional compo-nents, perform the receiver function. Tube-type fuzes detect changes in the oscillator plate current brought about by changes in the plate load imped-ance. The antenna impedance is part of the plate load and the presence of a target return signal causes a variation in the antenna impedance. The only component needed to filter the RF signal in a tube-type fuze is a bypass capacitor. Transistor-type fuzes use a diode, load resistor and bypass capacitor to rectify and filter the changes in the RF signal across the impedance matching coil. Collec-tor or emitter current detection produces too small a signal because of the very low impedances of transistors. Both types of oscillators provide a sim-ilar output signal that is supplied to the signal pro-

cessor. A test point is brought out to the base of the monitor from the junction of the oscillator output and signal processor input. This test point is used in determining the oscillator sensitivity (O-sen) which is a measure of the oscillator’s reaction to a specified target (defined as an infinite plane) under specified conditions. The same test point is also used to determine the amplifier sensitivity (A-sen) which will be described later.

4-5.1.8.5.3. Noise Filter. A noise filter is used only in the solid-state versions of the MK 70-series fuzes and the MK 417/418 fuzes. It does not regu-late the supply voltage, but uses a Darlington amplifier to increase the effective value of a capac-itor in what would otherwise be a simple R-C filter. Battery noise is attenuated by about 40 dB or a fac-tor of 100.

4-5.1.8.5.4. Target Signal Generation. Figure 4-20 shows a vector diagram of typical engage-ment between an air target and a fuzed projectile on parallel, non-colliding paths. The target is used as the reference and, therefore, its velocity vector is added to that of the projectile. The trans-mitter radiates electromagnetic signal which forms the projectile antenna pattern. A target entering the pattern will intercept a portion of the signal and reflect part of it back into the fuze receiver. Since there is relative motion between the target and fuze, the path length of the signal continually changes. As the target and fuze close, the two-way path length of the signal changes. When this signal path length coincides with exact multiples of a half wave-length (λ /2) of the fuze transmitter fre-quency, the transmitted wave and the reflected wave will be either in or out of phase with each other. The two signals will mix in the detector cir-cuit, their absolute values will add when they are in phase and subtract when out of phase. After filter-ing, the remaining Doppler signal, which is a series of low frequency nulls and peaks, is processed by the fuze circuitry. The Doppler frequency is in the audio frequency (AF) range and the transmitted frequency is in the very high frequency (VHF) range. In general, the Doppler signal generated by an approaching target begins as a high frequency, low amplitude signal, then decreases in frequency and increases in amplitude until the point of closest approach. As the target recedes, the frequency of

Figure 4-19 Typical Projectile Electrical Field Radiation Pattern, Cross Section

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the Doppler frequency increases and the amplitude decreases. Figure 4-20 also shows a typical target signature. Its complex waveform is brought about because signals return from many surfaces of the target at the same time. Spherical targets are used for design testing in the laboratory and the field because they reflect signals which are predictable and, therefore, give results which can be correlated between test sites.

4-5.1.8.5.5. Target Burst Position Calcula-tions. The vector diagram used for the fuze Dop-pler calculations is shown in Figure 4-20 with the fuzed projectile located at time t1. At the wave-lengths that VT-RF fuzes operate, the signal return from the target has a center of reflection, or cen-troid, from which the return appears to be gener-ated and which is located several feet behind the nose of the target. This centroid may actually change position slowly as the projectile-to-target angle, θ, changes. The vector diagrams are based on the location of the centroid rather than the tar-get’s nose, which is shown as the zero reference point. The relative velocity, VR, between the target and fuze is given by VR = (VT + VP) cos θ where VT is the target velocity, VP is the projectile veloc-ity and θ is the off-projectile axis angle between VTand VP. The Doppler frequency is given by∆f=2 VR/ λ. If the fuze detonates the projectile at time t2, the main beam, which is approximately 20° wide, is aimed at the electromagnetic centroid of the target. The optimum angle, θop, is reached when:

θop = tan-1 VF/ VT + VP

where VF is the static projectile fragment velocity. The dynamic fragment velocity with respect to the target is given by:VFR = VT + VP /cos θop

The Doppler frequency at this optimum burst posi-tion is ∆fop = 2 (VT + Vp) cos θop/λ. These equa-tions do not allow for fragment slowdown. It is usually not significant over the short distance to the target.

4-5.1.8.6. Signal Processor. The function of the signal processor is to amplify, and integrate the tar-get return signal, while discriminating against unwanted background noise. The target signal is then compared with a fixed threshold voltage which, when exceeded, generates a firing pulse for the electric detonator. All the RF fuzes described in this chapter perform these same functions to varying degrees; however, the components used in the vacuum tube-type fuzes are quite different from those used in the solid-state type fuzes. The signal processor circuitry is contained in the two blocks shown in Figure 4-18 and labeled “amplifier” and “automatic gain control”.

4-5.1.8.6.1. MK 70-Series Fuze Tube-Type Sig-nal Processor. The vacuum tubes used in fuze cir-cuits severely limit fuze design flexibility. Although the tubes are very rugged, they have many limitations, such as their large size, long fila-ment warmup time, generation of microphonics, and high operating voltages. The size of the tubes limit the number that can fit into the amplifier space to five or six, one of which is the downstairs oscillator tube and another is the thyratron which generates the firing pulse. The filament warmup must take place before the earliest possible mechanical arming time of approximately 0.3 sec-onds in order to have circuit transient stability before fuze arming. Transients will cause the fuze to early function. Filament warmup cannot occur faster than the time it takes for the RE to come up to operating voltage, which is approximately 0.1 second at 70°F. The time limitations force the tube design to use directly heated cathodes which bring on additional constraints. Due to circuit complex-ity, tube circuits must be used which have the cath-ode at a.c. ground potential. Therefore, circuits like cathode followers and voltage regulators are impractical. Essentially, tube circuits are limited to those using simple diodes, triodes, pentodes and thyratrons. Tubes also generate internal micro-phonics during projectile flight. This type of noise contains frequency components above 1000 Hz, which limits the upper band edge of the amplifier. The use of high voltages also forces the capacitors to be relatively large to prevent voltage breakdown. Some resistors also have to be large to handle the higher power dissipation at the higher tube cur-rents.

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4-5.1.8.6.1.1. Bandpass Amplifier. Bandpass amplifiers are used in fuze designs to amplify the target return signal and minimize unwanted signals such as microphonics, battery noise and wave noise. Microphonics determine the high frequency band edge, and wave noise determines the low fre-quency band edge. Wave noise has lower fre-quency components than target signals because only the horizontal component of the projectile's velocity is applicable in the Doppler equation. RE noise is generally spread over a wide range of fre-quencies. Because part of the noise is in the band-pass limits and cannot be filtered, the gain of the amplifier is limited in the pass band. With these restrictions the amplifier design typically uses two pentode amplifier stages and enough R and C com-ponents at the input and output of each tube to pro-vide 12 db per octave of high and low pass filtering. The center frequency of the amplifier is generally somewhere between 300 and 500 Hz and the center frequency amplification is limited to a factor of approximately 600. Typical A-sen response curves are shown in Figure 4-21 for the

tube-type and solid-state-type signal processors; also shown is the relative amplitude of wave noise in the domain. A-sen is defined as the threshold root-mean-square (rms) signal l evel of a four-cycle sine wave at a particular frequency that is applied to the input (pin 1) of the signal processor which just triggers the firing circuit. The definition of A-sen on older fuze MODs is similar except the sine wave is not limited to four cycles.

4-5.1.8.6.1.2. Amplifier Limitations. As stated above, for a given closing velocity there is an opti-mum angle at which the projectile should burst to obtain maximum lethality. At this same point there is a related Doppler frequency. If the fuze had to function only at this one set of conditions, the amplifier bandpass could be made very narrow. Under normal conditions the closing velocities will vary over a wide range. The tube-type amplifier, because of its bandpass limitations, can only pro-duce an optimum burst at a very low closing veloc-ity of about 2000 ft. per second. At higher closing velocities, which require higher optimum Doppler

Figure 4-20 Air Target and VT-RF Fuzed-Projectile Engagement, Vector Diagram

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frequencies, the A-sen decreases. The amplitude of the target return signal is also lower at these fre-quencies, so the only way the amplifier can see a signal sufficient in amplitude is to delay the gener-ation of a firing pulse until a lower Doppler fre-quency with a higher amplitude can cause triggering. This circuit behavior allows the bursts to be delayed more and more as closing velocities increase, which is obviously not desirable. This is the principal shortcoming of the tube-type amplifi-ers.

4-5.1.8.6.1.3. Automatic Gain Control (AGC). Tube-type fuzes have their performance degraded by wave noise when the fuze is below 1500 feet of altitude. The seriousness of the degradation depends on the height above the waves, the sea state and the flight-path of the projectile. Over calm water there is no degradation. To minimize the effects of wave noise on the fuze as well as that of any other noise source, the AGC circuit gener-ates a dc bias voltage whenever any persistent sig-nal (longer than about 200 ms) is detected. Air target signals generally last no longer than 40 milli-seconds. The negative dc bias voltage is generated by half-wave rectification and filtering of the

unwanted signal. The bias is then applied to the control grid of the first stage amplifier tube. The larger the dc bias, the greater the gain reduction. The resultant desensitization of the fuze amplifier allows the tube-type fuzes to have a limited func-tion when 150 ft. or higher above-sea-state three wave conditions. REs also occasionally produce severe noise which could cause early functioning if the AGC were not present.

4-5.1.8.6.1.4. Integrator Circuit. An integrator is used to minimize the effects of sharp impulses of noise, such as rain impact, microphonics, and some RE effects. The integrator requires a fixed energy level in a given time period to build its voltage up suf-ficiently to reach a firing level threshold. Noise spikes may have high voltage levels but their duration is very short; hence, very little energy is transferred. Four or more continuous cycles of a Doppler signal are needed before a firing level is reached. The dc voltage level built up in the integrator is positive and is added to the -7.5 volt bias on the grid of the thyratron. When the sum of the voltages reaches -2.0 volts, the thyratron will trigger and discharge the firing capacitor.

Figure 4-21 Wave Noise Amplitude Distribution and A-Sen Response Curves for VT-RF Fuzes

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4-5.1.8.6.1.5. Firing Circuit. Figure 4-22shows a schematic circuit diagram of the firing circuit (including the electric detonator and its shorting wire), the reed spin switch, the impact switch and the RE power supply. All even MODs of the MK 70-series tube-type fuzes incorporate the reed spin switch. Gun firing generates setback and centrifugal forces within the fuze. The setback force breaks the glass ampule of the RE and depresses the setback pin of the RFSD, thus unlocking the clock timing mechanism. The spin force causes the electrolyte to fill the spaces between the dry charged cells of the RE, unlocks the rotor detents and the escapement lever detents, provides drive for the clock timing mechanism, and opens the reed spin-switch, if present, thus removing the short across the firing capacitor. When the clock has run for approximately 0.4 seconds, the rotor of the RFSD is unlocked. The unbalanced rotor, then rotates due to centrifugal force to align the transfer detonator with the

electric detonator and lead. Just before full rotor alignment occurs, the shorting wire across the electric detonator is broken by a phenolic pin in the rotor. During the same interval, the RE voltage rises to approximately 95% of its full value within the first 0.1 second (at room temperature). As the RE voltage builds up, the 100-volt supply is applied to the firing capacitor through the charging resistor. The capacitor stores electrical energy and provides a very low impedance path to dump the energy through the electric detonator when needed. The rate of charge to the firing capacitor through a resistor is deliberately kept low so as to deny sufficient energy to the firing circuit to initiate the detonator until the projectile travels a safe distance from the gun (at least 200 feet). This RC delay provides a backup safety feature in the remote case of a clock failure. The RFSD is the primary safety device in the fuze. The carbon bridge electric detonator has an impedance of 0.7K to 15K ohms and requires only 500 ergs to fire.

Figure 4-22 MK 70-Series Fuze Tube-Type Firing Circuit Schematic

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4-5.1.8.6.2. MK 70-Series and MK 417/418 Fuze Solid-State-Type Signal Processors. Solid-state active components provide instant warm-up and are useful in a variety of circuits. Solid-state designs are therefore not subject to the same con-straints that limit vacuum-tube designs. What does restrict these designs is cost and complexity. Because projectile fuzes are used in large quanti-ties, cost-versus-complexity fuze design tradeoffs are always being made. The goal is to obtain high reliability combined with a high effectiveness against intended targets.

4-5.1.8.6.2.1. Bandpass Amplifier. The solid-state amplifier is of a bandpass design. An inte-grated circuit (IC) chip containing two operational amplifiers (op amps) is used with the necessary external RC components to establish the band edges. A-sen response curves for tube-type and solid-state amplifiers are shown in Figure 4-21. Comparing the two curves shows that the center frequency for solid-state amplifiers is approxi-mately four times higher and the firing threshold four times more sensitive than that of the tube design. Solid-state components do not generate significant microphonic signals and, since the RE voltage is filtered, the gain of the amplifier is not too restricted. The design of the amplifier response curve is accomplished by determining the target return signal at the maximum radial miss distance (RMD) desired for the fuze to function. At this RMD and for the highest expected closing velocity, the Doppler frequency and signal amplitude are determined for the optimum burst angle. Since the amplifier is followed by a four cycle integrator, the signal considered for initiating firing is simply the four cycles occurring immediately before the time of optimum burst. The center frequency and A-sen at this frequency are then determined. By repeat-ing this calculation at several lower closing veloci-ties an A-sen response curve is determined which will precisely compensate the burst position for different closing velocities at the specific miss dis-tance. However, since the O-sen and A-sen will be slightly different for each fuze, and different size targets will have different return signal levels, the best that can be expected with this type fuze design is to obtain a good average burst position for all expected conditions. Also, at closer miss distances

the signal level at the optimum angle will be larger. This will cause the burst to occur too soon and, therefore, reduce their effectiveness. To minimize this effect, the second op amp stage, which is iden-tical to the first stage in its small signal gain and frequency response, has a pair of opposing, series connected zener diodes in its feedback-gain-con-trol network. This causes the op amp to behave like a compression amplifier for signals above a minimum threshold value. This significantly improves the burst positions at closer miss dis-tances. At a typical optimum op value, for exam-ple, the detected target return signal can be 50 times greater at a 10 foot RMD than at a 60-foot RMD. The compression amplifier reduces this large signal range to less than 2 to 1 at the output of the bandpass amplifier. Another important advan-tage of the solid-state design with its higher fre-quency bandpass is that the effect from wave noise is significantly decreased. With a sea-state III con-dition this design is not affected down to 500 feet above the surface and will perform with reduced burst radius down to about 50 feet.

4-5.1.8.6.2.2. Automatic Gain Control (AGC). The solid-state fuze is subject to wave noise prob-lems, although to a lesser degree. The AGC cir-cuitry performs the same task as in the tube-type but differs in that it takes the output signal from the amplifier, rectifies it and produces a dc bias which is applied to the gate of a field effect transistor (FET), instead of controlling the gain of the ampli-fier. The FET precedes the bandpass amplifier and is in series with the signal path. The FET is used as a variable resistor in a voltage divider network; the AGC voltage applied to the FET gate thus deter-mines the resistance. Because of AGC design dif-ferences, the solid-state fuze is not affected as much by wave noise as a fuze with a tube-type AGC. Even though the fuze can produce reason-able bursts down to about 50 feet above sea-state III waves, the target itself can be between the pro-jectile and the ocean. Therefore, the fuze is effec-tive against air targets flying as low as 20 feet above the ocean surface.

.

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4-5.1.8.6.2.3. Integrator Circuit. The integra-tor circuit serves the same purpose in solid-state fuzes as in tube type-fuzes. The big difference is that the need for the circuit is considerably reduced because of the decrease of background noise sources. When the dc level of the integrator reaches the trigger level of the programmable uni-junction transistor (PUT), the PUT dumps the inte-grator capacitor charge into the gate circuit of the silicon controlled rectifier (SCR) which is the equivalent of a thyratron in its action. The PUT is needed in the circuit as an impedance matching device between the relatively high impedance of the integrator and the low impedance of the SCR gate. When the SCR triggers, it discharges the fir-ing capacitor.

4-5.1.8.6.2.4. Firing Circuit. Figure 4-23 is a schematic circuit diagram of the firing circuit, including the electric detonator and its shorting wire, the reed spin switch, the impact switch and the RE power supply. All even MODs of the MK 70-series solid state fuzes incorporate the reed spin switch. The MK 417/418 MOD 0 fuzes do not incorporate the reed spin switch. The circuit oper-ates the same as that of the MK 70-series tube-type fuzes. The SCR performs the identical function of

the thyratron and behaves like a shorting switch when its gate is biased on. The RE voltage has a nominal value of 30 volts and the electric detonator has an impedance of 3 to 7 ohms. The same safety features are incorporated into this fuze as in the MK 70-series tube-type fuzes. Because the electric detonator has a very low impedance and requires approximately 10 times more energy to fire than the carbon bridge detonators, this fuze design has an improved handling safety, particularly during manufacture.

4-5.1.8.7. Modes of Operation of Firing Cir-cuit for SD-Type Fuzes. During normal operating conditions, the fuze firing circuit will be com-pletely charged and armed after approximately 0.4 ± 0.1 second of flight. The fuze will remain in this condition until such time as one of the following events occurs:

a. The fuze encounters an air target, thereby triggering its firing circuit as described above.

b. The fuze impacts the target, crushing the impact switch, which then performs the same shorting function as the thyratron or SCR. The remainder of the action is the same as described above.

Figure 4-23 MK 70-Series, MK 417, MK 418 Fuze Solid-State Firing Circuit Schematic

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c. The fuze senses no target and the projectile continues its flight. If fired at a sufficiently high QE, normal spin decay will allow the reed-spin switch to reclose. This switch provides the same shorting function as the impact switch or the thyra-tron and SCR. It discharges the firing capacitor and initiates the firing train. It is designed to reclose at a range exceeding 10,000 yards or a min-imum of 20 seconds of flight time. If the QE is below that which allows SD action, the impact switch will close on contact with water or land and detonate the projectile or the fuze could function in the proximity mode

4-5.1.8.8. Modes of Operation of Firing Cir-cuit for NON-SD-Type Fuzes. If the fuze is a non-SD type, it can be used against air targets the same as the SD-types. However, its intended role is shore and ship topside bombardment. Since both of these targets generally are located at long range, the SD-types have to be excluded to prevent in-flight self-destruction. If the intended targets are at flight times below 20 seconds, then either type fuze can be used. In the bombardment role the fuze functions as follows:

a. The fuze processes the very large return signal from either the water or land surface. It may not recognize the weaker return from a small sur-face target. In this case, the AGC circuit has sev-eral seconds to desensitize the fuze before it reaches the target area. This process causes the fuze to burst over land or water at a height of 20-40 feet. The target is damaged primarily because it is in the vicinity of the air burst position. If the target is large enough, such as a capital ship, then the sig-nal return is modified somewhat, thus influencing the burst height to a more realistic value.

b. If the Doppler frequency fails to build up a sufficient signal to trigger the fuze, then the impact switch will finish the task.

4-5.2. Fuze MK 73 (5” Variable Time-Radio Frequency).

4-5.2.1. General. MOD 13 is the latest; 8 through 11 are obsolescent. The exterior view of MK 73 fuze, as shown in Figure 4-24, is the same for all. The fuze is used against aircraft beyond a

range of 500 yards. The fuze has a limited effec-tiveness against airplanes below 200 feet. without self-destruct feature can also be used against per-sonnel; light equipment, installations, and surface craft.


4-5.2.2.1. Self Destruct Features. Odd-num-bered through 13 have no self-destruct feature; their noses are color coded green. Even numbered, including 8 and 10, do have a self-destruct feature incorporated in the RFSD and are identified by a white plastic nose. MOD 12 is documented but was not produced. The nose for the tube-type fuzes is crimped integral to the threaded steel

Figure 4-24 Fuze MK 73 (Variable Time-Radio Frequency), Cutaway View

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insert. The nose for the solid-state-type fuze is cemented in place and a locking lip is rolled into a groove, but no pressure is applied to the plastic.

4-5.2.2.2. MOD 13. The solid-state MK 73 MOD 13 replaces the earlier (vacuum tube) models of the MK 73 VT fuzes. This fuze contains an impact switch to ensure point detonating backup to the primary radio proximity functioning mode. The MK 42 MOD 1 or 3 RFSD, a non-self-destruct type, is used in the MK 73 MOD 13 fuze. These RFSDs have been designed to arm within 780 to 1,400 feet from the gun muzzle. Physically, the MK 73 MOD 13 is interchangeable with the vac-uum tube MK 73 4 through 11. The exterior con-figurations (thread, ogive, and intrusion) are identical. Changes were made to the RFSD to increase the handling safety of the electric detona-tor and safety and reliability in gun firing.

4-5.2.3. Use.5-inch, HE-VT and VT-NONFRAGprojectiles

4-5.2.4. Physical Characteristics.MODs 8 and 9

Specification ................................. WS 14156MOD 10

Specification ................................. WS 14159 Drawing ........................................... 2513034 MOD 11 Specification ................................. WS 14159 Drawing ........................................... 2513035 MOD 13 Specification ................................. WS 14370 Drawing ........................................... 2512221All

Weight...........................................4.3 pounds Length ..........................................9.83 inches Intrusion....................................... 5.11 inches Maximum diameter......................2.72 inches Sleeve diameter............................2.00 inches Thread size.........................2.350-10NS-2RH Thread length .................................. 0.71 inch

4-5.2.5. Fuze Components.MOD 13

Monitor..................................MK 37 MOD 0 Reserve energizer ..................MK 38 MOD 0 RFSD...........................MK 42 MOD 3 and 1

Electronic detonatorMK 71 MOD 0; n-leadstyphnate, lead azide, PETN

Rotor detonator....MK 64 MOD 0; lead azide Booster lead-in

Early fuzes ........................................ TetrylLater fuzes ....................................PBXN-5

Booster ....................... MK 39 MOD 0; tetryl

4-5.2.6. Arming.Spin No arm.................. 40 revolutions per second All arm ............... 145 revolutions per second Normal spin........ 254 revolutions per second Arming distance ................. 780 to 1,400 feet

4-5.2.7. Function.Type............. Proximity, impact, self-destruct

(even no. fuze)Delay ........................................Instantaneous

4-5.2.8. Packing.360/pallet; 41 cubic feet; 1,919 pounds

(estimated gross weight)

4-5.3. Fuze MK 417 MOD 0 (76mm Variable Time-Radio Frequency).

4-5.3.1. General. The MK 417 MOD 0 fuze (Figure 4-25) is a short-instrusion version of the MK 72 MOD 17 VT-RF fuze and is used in 3-inch, 50 caliber and 76mm, 62 caliber guns. It has no self-destruct feature, but has an impact function backup feature. Its nose is colored beige. This fuze meets the contour dimensions of MIL STD-333 except for a longer thread length running almost the full length of the intrusion portion of the fuze and a slightly larger sleeve diameter below the thread to provide additional weight to meet the 76mm HE round weight requirement. The fuze is used against aircraft and missiles beyond a range of 500 yards but exhibits a decrease in effectiveness

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against aircraft and missiles below 200 feet. It also may be used against personnel, light equipment, installations, and surface craft.

4-5.3.2. Description. The MK 417 VT-RF fuze is a short intrusion solid-state fuze containing a MK 47 MOD 0 monitor, a MK 43 MOD 0 reserve energizer, a MK 42 MOD 3 RFSD, and an 11.0-gram CH-6 booster as principal functional ele-ments. Changes were made to the MK 47 MOD 0 monitor to increase its effectiveness over water and to the reserve energizer to increase its performance to accommodate greater spin eccentricities of the projectile.

4-5.3.3. Use.76mm, 62 caliber, HE-VT and VT-NONFRAG Projectiles

4-5.3.4. Physical Characteristics.Specification..................................... WS 19609Drawing............................................... 5467652Weight ............................................2.10 poundsLength ........................................... 5.984 inchesIntrusion .......................................... 2.21 inchesMaximum diameter ......................... 2.40 inchesSleeve diameter .................... 1.827 max. inchesThread size ..............................2.000-12UN-2AThread length .................................. 1.51 inches

4-5.3.5. Fuze Components.Monitor .....................................MK 47 MOD 0Reserve energizer......................MK 43 MOD 0RFSD ........................................MK 42 MOD 3

Electric detonator ........ MK 71, MOD 0; leadstyphnate, lead azide, PETN

Rotor detonator ...MK 64 MOD 0, lead azide Booster lead-in .................................PBXN-5Booster assembly (Dwg 5468148) ...........CH-6


No arm................................................ 900 g’s All arm ............................................ 1,385 g’sSpin

No arm.................. 48 revolutions per secondAll arm ............... 145 revolutions per second

Arming distance......................700 to 1,330 feet

4-5.3.7. Function.Type .........................Proximity airburst, impactDelay............................................Instantaneous

4-5.3.8. Packing.576/pallet; 30.2 cubic feet; 1,378 pounds

Figure 4-25 Fuze MK 417 MOD 0 (Variable Time-Radio Frequency), Cutaway View

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4-5.4. Fuze MK 418 MOD 0 (5’ Variable Time-Radio Frequency).

4-5.4.1. General. The MK 418 MOD 0 fuze (Figure 4-26) is a short-intrusion version of VT-RF MK 73 MOD 13 fuze, and eventually will replace it in 5-inch, 54 caliber Navy guns. It has no self-destruct feature, but has an impact function backup feature. Its nose is colored green to distinguish it from the MK 417 fuze, since both fuzes can be screwed into the same explosive cavity. This fuze meets the contour dimensions of MIL-STD-333. The fuze is used against aircraft and missiles beyond a range of 500 yards but exhibits a decrease in effectiveness against aircraft and missiles below 200 feet. Because of its impact backup feature, it also may be used against personnel, light equip-ment, installations, and surface craft.

4-5.4.2. Description. The VT-RF MK 418 fuze is a short intrusion solid-state electronic fuze con-taining a MK 48 MOD 0 monitor, a MK 43 MOD 0 reserve energizer, a MK 42 MOD 3 RFSD, and an 11.0-gram CH-6 booster as the principal functional elements. Changes were made to the MK 48 MOD 0 monitor to increase its effectiveness over water and to the MK 43 MOD 0 reserve energizer to increase its performance for greater spin eccentricities of the projectile.

4-5.4.3. Use.5-inch, HE-VT projectiles

4-5.4.4. Physical Characteristics.Specification .....................................WS 19610Drawing ...............................................5178407Weight ......................................... 1.975 poundsLength ........................................... 5.984 inchesIntrusion ......................................... 2.21 inchesMaximum diameter......................... 2.40 inchesSleeve diameter...................... 1.77 max. inchesThread size.............................. 2.000-12UN-2AThread length ...........................0.914 max. inch

4-5.4.5. Fuze Components.Monitor .....................................MK 48 MOD 0Reserve energizer......................MK 43 MOD 0RFSD ........................................MK 42 MOD 3

Electric detonator ........MK 71, MOD 0; leadstyphnate, lead azide, PETN

Rotor detonator ...MK 64 MOD 0, lead azideBooster lead-in .................................PBXN-5

Booster assembly (Dwg 5468148)............CH-6

Figure 4-26 Fuze MK 418 MOD 0 (Variable Time-Radio Frequency), Cutaway View

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No arm ................................................900 g’s All arm.............................................1,385 g’sSpin

No arm .................. 40 revolutions per second All arm................ 145 revolutions per secondArming distance ..................... 780 to 1,400 feet

4-5.4.7. Function.Type......................... Proximity airburst, impactDelay ........................................... Instantaneous


4-5.5. M728 and M732 Controlled Variable Time - Radio Frequency Fuzes.

FOR PROXIMITY FUNCTIONING, DO NOT SET CONTROLLED VARI-ABLE TIME FUZES TO A TIME MORE THAN 50 SECONDS EARLIER THAN THE ESTIMATED TIME OF FLIGHT BECAUSE OF THE LIM-ITED FUNCTIONING LIFE OF THE RESERVE ENERGIZER. TO ASSURE PROXIMITY FUNCTIONING AT LONG RANGES, SET CVT-RF FUZES TO A TIME THAT IS AT LEAST 10 SECONDS LESS THAN THE ESTI-MATED TIME OF FLIGHT.

TO ASSURE PD FUNCTION OF ALL CVT FUZES, SET THE FUZE TO THE TIME OF FLIGHT PLUS AT LEAST 15 SECONDS. THIS ALLOWS FOR CAP SLIPPAGE AT GUN FIRE, WHICH MAY RESET THE FUZE FROM PD TO PROXIMITY MODE.

FOR CVT FUZES M513, M514, AND M728, PROXIMITY FUNCTION IS NOT ASSURED FOR SETTINGS LESS THAN 5 SECONDS; POINT DETO-NATING FUNCTION MAY RESULT INSTEAD. UNLESS TACTICAL CIR-

CUMSTANCES DICTATE OTHER-WISE, CHOOSE PROXIMITY SETTINGS OF AT LEAST 5 SEC-ONDS.

IF FIRING CVT PROJECTILE FUZES OVER CRESTS OR RIDGES, A SET-TING SHOULD BE CHOSEN SUCH THAT PROXIMITY ENABLE IS DELAYED UNTIL PROJECTILE HAS PASSED IRREGULARITY. IF ARM-ING OCCURS AT OR AHEAD OF IRREGULARITY, PROJECTILE MUST CLEAR IRREGULARITY BY 500 FEET (167 YARDS) OR MORE.

WHEN CVT FUZE IS SET FOR PROXIMITY FUNCTIONING, AIR OBSERVATION POST MAY SAFELY BE USED TO DIRECT FIRE. HOW-EVER, DO NOT SET UP POSTS BETWEEN WEAPON AND TARGET. HAVE FRIENDLY AIRCRAFT NO CLOSER THAN 2400 FEET (800 YARDS) TO TARGET.

4-5.5.1. General CVT-RF Fuze. CVT-RF and VT-RF fuzes employ similar components and oper-ate on the same theoretical principles for target detection and firing point determination. However, CVT-RF fuzes, unlike VT-RF fuzes, have target detection circuitry that is specifically designed to sense ground and water surface targets, as opposed to air, in order to provide a height of burst.

4-5.5.1.1. Background. The M728 and M732 CVT-RF fuzes are active radio-frequency proxim-ity fuzes designed for use in the nose of high explo-sive loaded, fragmenting projectiles (Figures C-1and C-2). The fuzes are primarily proximity fuzes with superquick impact functioning as a backup. Time scale settings of 5 to 100 seconds (5 to 150 seconds for M732) permit selection of variable tar-get sensing activation times for the proximity mode. A time setting is selected which coincides with the estimated time-to-target. Function in the proximity mode is inhibited until a nominal five seconds before the set time for the M728 fuzes, and 5 to 7 seconds before the set time for the M732 fuze. The impact backup is enabled at fuze arming at approximately 2.75 seconds (833 feet minimum for the M732 fuze in the 16"/50 gun) after firing

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and is thereafter operable throughout flight. Figure 4-27 shows the critical in flight events for the M728 fuzes and Figure 4-28 shows the approxi-mate arming position for the M732 fuze. The aver-age radius of sensitivity is about 100 feet for the M513 and M514 fuzes (30 feet for M728 and M732). The M513A2 and M514A1 fuzes were originally developed by the Navy specifically for use against surface targets in close support of friendly forces and were placed in production by the Army. The M728 and M732 fuzes are product-improved fuzes developed by the Army for Army artillery projectiles.

In 1972, the Army released the M728 fuze to production as a solid-state replacement for both the M513 and M514 fuzes. The M728 fuze was adapted to the 5"/38 and 5"/54 projectiles in Octo-ber 1977 because the M513 and M514 fuzes were no longer manufactured or stockpiled by the Army. To use the Army-procured fuzes in Navy projec-tiles, an adapter is required to accommodate the larger fuze threads of Navy projectiles. The adapter supports and strengthens the fuze and per-mits compatibility of the fuze ogive and threads with that of the projectile. The M732 fuze is used in the MK 143 MOD 0 HE-CVT 16"/50 projectile without being first assembled into a “Fuze and Adapter Assembly.”

Figure 4-27 Arming Sequence of M513A2, M514A1, and M728 CVT Fuzes

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4-5.5.1.2. Fuze Design Evolution. Between 1946 and 1953, many design changes were made to the M513 and M514 fuzes, mostly to extend shelf life of the various components, increase reliability or improve miniaturization. Safety has always been excellent in the handling and use of proximity fuzes. Some of the changes made were to build more compact reserve energizers (RE), eliminate mercury (primer unshorter) switches, add clock-type rear fitting safety devices (RFSD) to improve arming time accuracy, add additional oscillator fre-quency ranges to improve electronic countermea-sures (ECM) protection, and reduce the size of the glass envelopes of the miniature vacuum tubes. The electronic circuits themselves changed very little; the passband and the sensitivity were kept the same. By 1956, a new battery chemistry system, using lead-lead dioxide cells and fluoroboric acid electrolyte, was available to replace the existing

carbon-zinc cells and chromic acid electrolyte sys-tem. For the same volume, it could deliver signifi-cantly more power and operate over a wider temperature range with lower output impedance. The above changes kept pace with the changes in the MK 70-series fuzes since both types of fuzes were designed at the same laboratory under the direction of the same individuals. The only fuze models actually adapted to Navy projectiles were the latest versions available. An improved design change was to build a solid-state version of the M514A1 fuze which was initially designated as M514A1/E1. After it was in production, the Army assigned the designation M728 because the front case was coated and the firing circuit was modi-fied. Both models of the solid-state fuzes kept most of the original hardware parts of the M514 fuzes as well as the CVT mechanism and the RFSD with only a couple of changes to meet MIL-STD-1316

Figure 4-28 Arming Sequence of M732 CVT Fuze in MK 143 Projectiles

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safety requirements. The oscillator was changed to a non-body radiator design which allowed the fuze to operate in almost any length projectile, thus eliminating the need for two fuzes such as the M513 and M514, which are both body-radiator designs. The most recent design M732 fuze uses a similar oscillator and amplifier as the M728 fuze, a new reserve energizer (PS115), an electronic timer, a new safety and arming module, and a shorter booster.

4-5.5.1.3. Design Features. The current CVT-RF fuzes in the Navy stockpile provide for a general purpose proximity fuze which can be used in a variety of surface target and ship topside applications. The unique design feature of these fuzes is their CVT setting which allows projectiles to be fired to ranges just beyond friendly troops without the danger of the fuze early functioning. Since this feature allows the oscillator to be on the air for only the last five to seven seconds before set time, it has an added ECM advantage in the presence of jammers or other interfering signals. The fuzes also have excellent operability, good ECM resistance and provide good burst heights for a variety of targets. The fuzes have an impact feature which can be set to operate independently of the proximity mode. An impact circuit will operate as a backup feature when the fuze is set in the proximity mode. The fuzes are not designed for use against air targets as they are very insensitive to targets which have small radar cross sections. However, under emergency conditions, when no other proximity type fuze is immediately available, CVT-fuzed projectiles can be fired at air targets with one or both of the following techniques. For targets approaching at any altitude, they can be used the same as the VT-RF fuzes. Because their burst radius is significantly smaller than that of a VT-RF fuze, they will be much less effective; however, their effectiveness will still be greater than that obtained with mechanical time or point detonating fuzes. For targets approaching at an altitude below 100 feet, the burst radius can be effectively increased by aiming the gun so that the bullet will descend to an altitude approximately 25 feet above the surface at a point just ahead of the target. The resulting surface-triggered proximity burst will also produce lethal fragments in the direction of the target.

NOTEFiring the CVT-fuzed projectile at targets to which the flight time is less than the CVT set time will allow only point deto-nating bursts. The fuzes must be set to a CVT time several seconds shorter than the time of flight in order to ensure prox-imity functioning. For reliable selection of VT action, set all CVT fuzes for 7 sec-onds or longer.

4-5.5.2. Physical Description of the M728 CVT Fuze. The color of the M728 fuze front case is black because of the anti-static coating. The turning capsule assembly consists of the front case, monitor, reserve energizer and switch ring assem-bly. Figure 4-29 is a quarter section view of the M728 fuze. The fuze subcomponents identified are: front case, sleeve, monitor, reserve energizer, switch ring, rear fitting safety device, auxiliary det-onating fuze with booster, thread adapter sleeve, and holding ring. Projectile differences dictated that the overall fuze and adapter profile, threads, intrusion lengths and weights differ. Table 4-3 lists the pertinent data for the M728 fuze. Table 4-6lists the pertinent data for the MK 360 fuze and adapter assemblies, respectively.

4-5.5.3. The M728 Thread Adapter Sleeve and Holding Ring. The thread adapter sleeve is made of steel and serves two purposes. It makes it possible for the smaller thread of the CVT fuze to be matched to the larger thread of the Navy projec-tiles and it provides a stronger structure which in conjunction with the steel holding ring reinforces and supports the aluminum body of the fuze. It was determined that under worn gun conditions, especially in the 5"/54 gun, the aluminum body of the CVT fuzes was marginal in strength. The steel adapter and ring are protected from corrosion by a thin coating of either cadmium or zinc chromate. The adapter that uses the polycarbonate plastic shield also has the thread for the shield. The fuze is screwed into the adapter and tightened to a torque of 60 foot-pounds. The support ring is screwed into the bottom of the sleeve and torqued to 30 foot-pounds. The fuze and adapter assem-blies have to be assembled into the projectile and properly torqued to 95 foot-pounds.

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Figure 4-29 CVT Fuze M728, Quarter Section View

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Table 4-3 CVT-RF Fuze M728, Characteristics

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Table 4-4 CVT-RF Fuze and Adapter Assembly MK 360 , Characteristics

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4-5.5.4. Waterproofing. Waterproofing is achieved by a series of gaskets that serve to back up the sealing effect of the various threaded sec-tions of the fuze and adapter.

4-5.5.5. Setting of Fuze M728. CVT fuze M728 is normally set at the depot on a time setting. However, certain tactical situations may require other settings. In that case, settings must be made manually with either of two Navy fuze setting wrenches, NSN 1020-00-382-6910 or NSN 5120-00-623-0194, or with Army's Fuze Setting Wrench M27, NSN 1290-00-764-7761, since Navy auto-matic fuze setters cannot accommodate this fuze.

4-5.5.6. M728 Operation. When the fuze is set and projectile is fired, setback and spin forces break the ampule and distribute the electrolyte between the reserve energizer plates. Simultane-ously the clock in the rear fitting begins to run. Since the ground or common return to the reserve

energizer is not complete, the proximity circuit is not actuated. At a nominal 2.75 seconds after fir-ing, the rear fitting mechanically removes a short circuit from across the primer (Figure 4-30), which then completes the activating of the impact firing circuit. At the set time minus 5.0 seconds, the RFSD completes a circuit to the reserve energizer, which activates the proximity circuits. At the set time minus 3.0 seconds, the RFSD acts to remove a short, which allows the proximity firing condenser to charge in 0.4 second. The fuze is then fully acti-vated in the proximity mode at the set time minus a nominal 2.6 seconds. From this time until the end of the flight, the unit functions as a proximity fuze to detonate the projectile above the target. In the event that the proximity circuit fails to function, the impact device in the nose of the fuze detonates the projectile on impact by discharging a second inde-pendently charged capacitor through the primer.

Figure 4-30 Operational Sequence of Projectiles Fuzed with Controlled Variable Time Fuzes M514 and M728

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4-5.5.6.1. Temperature. M728 fuze is operable over a temperature range of -20 to 130 degrees F.

4-5.5.6.2. M728 Safety Features. CVT-RF fuzes are among the safest fuzes in the U.S. Navy. Many design features are provided to ensure safe handling, safety in the bore, and freedom from muzzle bursts. Rough handling may cause damage, resulting in abnormal operation or duds, but it is improbable that such treatment will be hazardous. A severe blow to the fuze (such as dropping the fuzed projectile) does not reduce safety but may decrease operability and may even render the fuze a dud if the battery ampule is shattered. If dropping occurs within 1 minute before loading into the gun and firing, the round has a high probability of operating normally. After 1 minute the round is still safe to fire, but reliability degrades rapidly. Components contributing toward safety of the CVT-RF fuze are the reserve energizer, the charging resistor, the centrifugal detents, the setback pin, the mechanical clock-controlled detonator unshorting gate, and the AD fuze. The features of these components have been described in the preceding paragraphs.

4-5.5.6.3. Tracers. Tracers cannot be used with CVT fuzes. Ionization of the tracer gasses reduces the effectiveness of the radio system and, if coinci-dent with the period of normal influence action, can effect a buildup of a false target signal causing detonation when arming is completed.

4-5.5.6.4. Atmospheric Effects. Lightning, fir-ing into rain clouds, or heavy rainfall can result in a decrease in operability.

4-5.5.6.5. Chaff. A very dense mass of window jamming chaff can produce early airbursts.

4-5.5.6.6. Gun Age. The reliability is decreased for CVT fuzes fired from very old guns as a result of excessive firing shock. Instability of the projec-tile, caused by either characteristic yaw or by bal-loting in a worn barrel, can also affect fuze performance.

4-5.5.6.7. Antiaircraft (AA). CVT-RF fuzes should not be used against AA targets except as a last resort because of fuze low sensitivity.

4-5.5.6.8. M728 Life Expectancy. The M728 fuzes are past their life expectancy, but are still usable. The M728 fuzes were built in the early 1970’s and only expected to last 15 years when the M728 cut fuzes were to replace them.

4-5.5.7. Marking. The following markings appear on the fuze:

Fuze DesignationLot No.Manufacturer's IdentificationNavy Acceptance StampThe metal front case insert bears the marking

FUZE & ADAPTER ASSY MK _____ MOD _____.

4-5.5.8. Physical Description of the M728. This section will provide greater details on the mechanical or physical aspects of the fuze design. A later section will provide greater details on the electronic RF aspect of the design.

4-5.5.8.1. M728 Turning Capsule. The turning capsule consists of the front case and body, moni-tor, reserve energizer (RE) and the switch ring assembly.

4-5.5.8.2. M728 Fuze Front Case and Body. The front case consists of a plastic nose which acts as the radome for the fuze transmitter. The thermo-plastic resin material is polyphenylene oxide (PPO) which is strong, has high melting temperature, and has excellent dielectric properties. The surface of the front case is coated with an anti-static material which has a resistance of between 1.0 and 20.0 megohms when measured between the tip of the nose and the lower extremity. The body is made of steel and is protected from corrosion by cadmium plating with a supplementary chromate treatment. The body contains the crimp groove which holds the front case, has an integral cavity which acts as the amplifier shield can, and the outer surface has a fuze setter slot with a setting line inscribed in the middle. The front case is attached to the body after the oscillator assembly is completed. It is cemented into the crimp groove and then while being held firmly in place the crimp lip is pressed into place. The lip applies no significant force to the plastic but only acts as a locking device.

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4-5.5.8.3. M728 Fuze Monitor. The monitor contains the electronic subcomponents of the fuze. There are two distinct electronic systems in the monitor; the transmitter-receiver (T-R) and the sig-nal processor. The T-R components are mounted on top the cavity of the body and the signal pro-cessing components along with the impact switch are mounted inside the body cavity which also acts as the RF shield can.

4-5.5.8.3.1. M728 Fuze Transmitter-Receiver. The T-R assembly contains the RF transistor, printed circuit (PC) antenna, detector diode, load resistor, four RF chokes and a PC plate assembly board. The antenna is a thin strip of double sided printed circuit board which is formed into triangu-lar shaped longitudinal loop antenna. The appro-priate capacitances and inductances are formed on the antenna by segments in the copper cladding and the dielectric of the PC board between the seg-mented sections. The RF transistor, detector diode, load resistor, and four RF chokes are soldered to the bottom inside of the formed antenna. The com-pleted antenna assembly is stacked above a molded plastic antenna positioner and an oscillator plate assembly PC board. A two-part foam potting com-pound is injected into the oscillator cavity through a small hole in the body. The foam provides the necessary shock mounting needed for the high G application for which this fuze is used.

4-5.5.8.3.2. M728 Fuze Signal Processor. The signal processor contains the remainder of the elec-tronic components used in the fuze as well as the mechanical switch which provides the impact for the fuze. The components consist mainly of resis-tors, capacitors, transistors, integrated circuits and diodes assembled onto a PC board.

4-5.5.8.4. M728 Fuze Power Supply Assem-bly. This assembly consists of the PS116 reserve energizer (RE) and the switch ring assembly. The PS116 is a dry-charged battery contained in a zinc-plated steel can. The RE supplies the electrical power for the fuze circuitry and also contains elec-trical leads which provide circuit connections between the signal processor, the switch ring assembly and the electric primer. The RE supplies one voltage, nominally 30 volts, and consists of a stack of plated electrodes with appropriate insula-

tors and spaces between each plate. The lead side of one plate, an insulator and the lead dioxide side of the next plate form a single cell. The RE stack consists of many of these cells. The center of the stack is open to accept a glass ampule containing an electrolyte fluid, fluoroboric acid, and a breaker plate. Projectile setback and spin forces cause the glass ampule to shatter and then allow the electro-lyte to fill the spaces between the plates. The stacked plates with the ampule inside, the turret wired to the top, the breaker plate beneath the stack and the baseplate wired to the bottom are potted with plastic and then inserted into the can from the bottom. The can is crimped over the baseplate to hold the assembly together. The RE is inserted into an outer can and retained in place by rolling a small crimp groove into the outer can at the top edge of the RE. The fuze power supply assembly consists of the power supply and outer can assembly with the switch-ring can attached. The switch-ring assembly provides the electrical switching func-tions for the CVT feature of the fuze. The switch-ring can contains the molded-plastic switch-ring, a gold plated lever and contactor, and a plastic insu-lator, all of which are parts of the CVT mechanism. The timing-disc assembly, which is attached to the shaft of the clock-drive mechanism, provides the remainder of the timing function. The switch-ring can and its parts are placed on the bottom of the outer can assembly with sufficient pressure to hold the internal parts firmly in place. The switch-ring can is then spot welded to the outer can assembly at three points. Alignment of the switch-ring compo-nents is maintained by insertion of the pins at the bottom of the outer can assembly into the proper holes in the plastic parts of the switch-ring.

4-5.5.8.5. M728 Timing Disc Assembly. The timing disc consists of two gold-plated pellets con-tained in a metal housing at two different levels. A retaining gate keeps the pellets in the housing until the proper time for their release. The timing disc assembly is attached to the shaft extending from the top of the rear fitting safety device. As the clock runs, it allows the pellets to be released at the time determined by the CVT set time. One pellet is released approximately five seconds before the CVT set time. This pellet is held against two pins extending from the power supply assembly by cen-trifugal force. In the M728 fuze the RE ground is

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connected to the ground end of a resistor in the noise-filter circuit. This activates the fuze circuitry and the oscillator comes on the air. Approximately two seconds later, which is three seconds before CVT set time, the second pellet is released. Cen-trifugal force causes this pellet to press against the lever, which unshorts the firing capacitor in the electronic portion of the fuze. From this point on the fuze can function either in the proximity mode or with impact backup.

4-5.5.8.6. M728 Rear Fitting Safety Device (RFSD). The MK 15 MOD 0 RFSD is used in the M728 CVT fuze. The RFSD provides a bore safety device and a timing mechanism to allow the electric primer to be unshorted at a safe distance from the gun. It contains a mechanical clock mechanism, setback pin, centrifugal detents, and a centrifugal actuated switch to unshort the primer and connect it to the firing circuit. The setback pin and centrifugal detents lock the clock escapement lever. Two independent environmental forces, set-back and spin, acting simultaneously, are required to allow the RFSD to arm. In actual use these RFSDs have demonstrated exceptional safety char-acteristics. The RFSD is cylindrical in shape, with the lower section having a reduced diameter, which allows the RFSD to seat on a holding ring. The explosive output of the RFSD primer transfers to an auxiliary detonating fuze explosive train.

4-5.5.8.7. M728 Auxiliary Detonating Fuze (Aux Det). The MK 52 MOD 0 auxiliary detonat-ing fuze for the M513 and M514 fuzes consists of an out-of-line firing train which incorporates two independent centrifugally actuated explosive rotors, and a booster charge. In the version used in the M728 fuze, one of the rotors has several centrif-ugal detent safety notches and a setback pin which cross-locks one of the two centrifugal detents. The safety notches allow the rotor to relock itself in case it advances during rough handling. Projectile spin forces align the firing train just a few feet out of the gun barrel. The booster cup, which is essen-tially the same as the MK 39 booster cup, is screwed into the back of the aux det housing.

4-5.5.8.8. Operation and Physical Description of the M732 CVT Fuze. This section will provide greater details on the operation and mechanical or physical aspects of the fuze design. A later section will provide greater details on the electronic RF aspects of the design.

4-5.5.8.8.1. M732 Proximity Setting and Point Detonating Functioning. The fuze is manually set with the M27 fuze setter wrench (or with one of the Navy setting wrenches NSN 1020-00-382-6910 or NSN 5120-00-623-0194). The setter is placed over the fuze and pushed firmly so that the steel catch engages the fuze setting slot. See Figure 4-31. The fuze body is then rotated to the desired setting. In the MK 45 Gun the setting is done auto-matically by the built-in fuze setter.

4-5.5.8.8.2. Impact Functioning. If impact functioning is desired, the fuze should be set for at least 15 seconds greater than the time of projectile flight. Setting the fuze on PD to obtain impact-only functioning should be avoided because possi-ble setting slippage can occur during gun firing. For proximity functioning, the fuze is set to a time that corresponds to the flight time to the target less several seconds. During flight, the fuze will not respond to proximity-sensed targets until approxi-mately 3 seconds before the set time for short times of flight and until approximately 5 seconds before the set time for long times of flight. To allow for both fuze timing tolerances and tolerances on the estimated time of flight, the fuze should be inten-tionally set to a time that is at least 10 seconds shorter than the estimated time of flight unless electronic countermeasure (ECM) conditions dic-tate a longer time. Setting the fuze for a time longer than the above value may cause the projectile to impact the ground before the fuze is able to respond in the proximity mode. Setting the fuze for a time that is significantly shorter than the value stated above is also not recommended because it increases the time of fuze broadcast and, therefore, both the time that the fuze is exposed to ECM and the range of flight over friendly territory in which the fuze is in a proximity sensing and firing condi-tion. On the other hand, setting the fuze to a time that is approximately 50 seconds or more shorter than the time of night may result in a proximity fir-ing failure due to the expiration of battery life.

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When proximity function is selected but fails to occur, two firing devices operate independently of each other to ensure that the fuze provides backup functioning at impact. If point detonating operation is selected, fuze impact with a target after the S&A is armed causes the S&A detonator to slide forward and strike the firing pin. However, for this selec-tion mode of fuze operation, the impact switch in the electronics does not operate to back up the mechanical firing system.

This fuze is a short intrusion fuze used in the 5" guns, but can also be used in 76mm and was used in the 16"/50 Navy projectile. The M732

Fuze is a continuous wave radio Doppler proximity fuze having improved electronics. It uses a fuze monitor (oscillator and amplifier) similar to the M728 Fuze. The fuze consists of two principal assemblies; a turning capsule assembly, and a sleeve assembly. The turning capsule assembly includes a front case and body assembly, a monitor, a power supply and an electronic timer. The sleeve assembly includes a detonator block, a safety and arming module, an explosive lead block, and a booster. Figure 4-32 is a quarter section view of the M732 fuze.

Figure 4-31 Controlled Variable Time Fuze M732/Fuze Setter M27 Interface

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Figure 4-32 CVT Fuze M732, Quarter Section View

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4-5.5.8.8.3. M732 Fuze Front Case and Body. The Front Case is formed from plastic and acts as the radome for the fuze transmitter. Its thermoplas-tic material is polyphenylene oxide (PPO) which is strong, has a high melting temperature, and has excellent dielectric properties. The surface of the front case is coated with material that prevents electrostatic charge buildup and which has a resis-tance of between 1.0 and 20.0 megohms when measured between the tip of the nose and the lower extremity. The body is made of steel and is pro-tected from corrosion by cadmium plating with a supplementary chromate treatment. The body con-tains a groove which holds the front case by crimp-ing. The sides and forward bulkhead form a cavity for the amplifier and power supply. The outer sur-face has a time setting slot with an index line inscribed alongside. The front case is attached to the body after the oscillator assembly is completed. Adhesive is applied to the crimp groove and then the crimp lip is deformed into place to lock the front case before the adhesive has set.

4-5.5.8.8.4. M732 Fuze Monitor. The Monitor contains the electronic subcomponents of the fuze. There are two distinct electronic systems in the monitor; the transmitter-receiver (T-R) and the sig-nal processor. The T-R components are mounted in front of the body cavity, and the signal processing components, along with the impact switch, are mounted inside the cavity, which also acts as the RF shield.

4-5.5.8.8.4.1. M732 Fuze Transmitter-Receiver. The T-R assembly contains the RF tran-sistor, antenna, detector diode, load resistor, five RF chokes and a PC assembly board. The antenna is a thin strip of double-sided printed circuit which is formed into a triangular shaped longitudinal loop antenna. The appropriate capacitances and induc-tances are formed on the antenna by segments in the copper cladding and the dielectric of the PC board between the segmented sections. The RF transistor, detector diode, load resistor, and four RF chokes are soldered to the bottom inside of the formed antenna. A fifth RF choke is soldered to the inside of the formed antenna at one side to pro-vide an electrostatic ground path for the otherwise isolated antenna segment closest to the fuze tip.

The completed antenna assembly is stacked above a molded plastic antenna positioner and an oscilla-tor plate assembly PC board. A two-part foam pot-ting compound is injected into the oscillator cavity through a small hole in the body. The foam pro-vides the support mounting needed by the compo-nents to resist gun firing shocks and other shocks and vibrations during transportation.

4-5.5.8.8.4.2. M732 Fuze Signal Processor. The Signal Processor contains the remainder of the electronic components used in the fuze, as well as the mechanical switch that provides the impact function for the fuze. These components consist of resistors, capacitors, transistors, integrated circuits and diodes assembled onto a PC board.

4-5.5.8.8.4.3. M732 Oscillator Assembly. The oscillator assembly contains an antenna, a silicon transistor, and other electronic components to form the radiating and detection system for the fuze. The antenna has a forward and rearward looking pattern, largely independent of the size of the pro-jectile, that is designed to provide an optimum burst height over a wide range of approach angels.

4-5.5.8.8.4.4. M732 Amplifier Assembly. The amplifier assembly contains a silicon integrated circuit amplifier and firing circuit. Other compo-nents are used for band pass-shaping of the ampli-fier response and for decision and enabling circuitry. The amplifier also contains a mechanical switch that functions the fuze electronically at impact should the proximity mode fail. This switch is enabled at turn-on of the fuze’s electron-ics, approximately 5 to 7 seconds prior to the set time., depending on the value of the set time.

4-5.5.8.8.5. M732 Power Supply Assembly. The Power Supply Assembly is a liquid reserve-type battery. The cells are steel-base stock with lead and lead dioxide coatings. The electrolyte (fluoroboric acid) is contained in a centrally located copper ampule. A combination of setback and spin opens the ampule and distributes the elec-trolyte into the cell stack to activate the battery. Finally, a dense insulating liquid (methylene dibro-mide) is dispensed to insulate the cells at their fill points.

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4-5.5.8.8.6. M732 Electronic Timer Assembly. The Electronic Timer Assembly delays turn-on of the fuze’s electronic circuitry until just prior to the set time. This decreases the exposure of the fuze electronics to electronic countermeasures, con-serves power supply energy, allows the fuze to be safely fired over obstacles such as hills, and pro-vides overhead safety across friendly territory. An impact mode can be selected during setting, and serves as a back-up system at all times should the proximity sensor malfunction. In operation, the fuze is set to the anticipated nominal time of flight (from 5 to 150 seconds) by rotating the nose sec-tion of the fuze. This, in turn, sets a variable inter-nal resistor which determines the rate at which the basic timing capacitor is charged by an integrated circuit multivibrator. At the end of the timing cycle, the fuze is turned on by a silicon switch. Accuracy of the timer is unaffected by spin condi-tions.

4-5.5.8.8.7. M732 Detonator Block Assembly. The detonator block assembly consists of a block with an electric detonator, a ratiometer, and an adhesive that bonds the block to the ratiometer.

4-5.5.8.8.8. M732 Safety and Arming Module. The Safety and Arming Module is a modification of the M125A1E3 booster. It arms the explosive train mechanically and provides a safe separation distance of the fuzed projectile from the weapon at the completion of arming. Both setback and spin are required for arming. Gun firing of the projec-tile, whether the fuze is set PROX or PD, starts into motion the arming of the safety and arming mecha-nism (S&A) with the setback lock moving down and latching under the influence of linear accelera-tion. As the spinning projectile exits the gun muz-zle, the spin locks swing out and allow the rotor to start moving. The rotor is unbalanced about its pivot axis so that it is driven by centrifugal force toward the armed position. A runaway escapement damps the rotor’s turning speed. The damping force provided by the escapement is proportional to the square of the projectile’s rate of spin. This type of damping results for a given type of gun in a rela-tively constant arming distance for the projectile independent of the projectile muzzle velocity. After the rotor is driven through an arc of about 75 degrees, it disengages from the gear train and snaps

to the fully armed position. A shutter then moves from above the stab detonator to uncover it from the firing pin, thus completing the arming process (explosive train aligned unshuttered). The fuze now functions in either the proximity or the point detonating mode, depending on the choice of fuze setting. The safe arming distance provided by the S&A module is most conveniently expressed in terms of the number of revolutions or turns made by the spinning projectile during the arming cycle. The M732 fuze S&A module is completely armed after 25 to 38 turns from the muzzle. The number of turns-to-arm in combination with the twist of the rifling establishes the arming distance for a given projectile. Most Navy guns have a twist of 25 cali-bers per turn; the corresponding minimum mechan-ical arming distance for this S&A module is 625 calibers. This corresponds to about 833 feet mini-mum for the 16"/50 projectile. After the rotor is driven through an arc of about 75 degrees, it disen-gages from the gear train and snaps to the fully armed position. The shutter moves from above the detonator and the rotor is locked in place by a cen-trifugally biased catch or detent mounted on the spacer. The fuze is then armed (explosive train aligned) and will function depending on the choice of fuze setting (PD or PROX).

4-5.5.8.8.9. M732 Barrier Lead Cup Assembly. The barrier lead cup assembly consists of a high alloy steel barrier and a 110-milligram PBXN-5 lead in a centrally located aluminum cup.

4-5.5.8.8.10. M732 Booster Cup Assembly. The booster cup assembly consists of an aluminum cup and a 5.85 gram CH-6 booster pellet.

4-5.5.8.9. Electronic-RF Description and Detailed Theory of Operation of Both CVT Fuzes. This section provides a detailed explana-tion of the theory of operation of CVT-RF fuzes. The process by which each component performs its task and how these tasks combine to perform as a fuze is described.

4-5.5.8.10. Design Considerations. The design of an active CVT-RF proximity fuze circuit is determined primarily by considerations of the RF echo area of the intended targets, the closing veloc-ity between the fuze and target, the limitations

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imposed by electronic circuit components, clutter from unwanted or nearby targets, background sources of radiation, and environmental conditions experienced during stockpiling, transporting and tactical employment.

4-5.5.8.10.1. Target Energy Considerations. Fragmenting projectiles are capable of inflicting significant damage to a variety of targets, such as ship topsides, trucks, radar sites, and personnel. Proximity fuzes of the RF type are designed to detect the presence of a nearby target by transmit-ting a high-frequency signal in the direction of the approaching target and detecting the small amount of RF energy reflected back from the target. Tar-gets on the water or ground surface may have radar cross sections (RCS) from very small to very large, but in all cases the surface itself represents a target with a very large RCS. Proximity fuzes fired at surface targets generally function on the energy reflected from the surface to provide the proper height of burst (HOB) in the presence of the actual target. The surface is generally not the intended target, but some object on the surface. If the target is personnel, there will be no signal return from anything but the surface. If the target is something like a vehicle in size, there will be some signal return from the vehicle which will be small in rela-tion to that produced by the surface. This small signal will act much like the modulation produced by irregularities in the surface and will cause a variation in the burst height. In the case of ship tar-gets, the superstructure may extend sufficiently above the water surface to be able to provide a return signal of its own, sufficient to cause trigger-ing of the fuze. Ship superstructures, with all their radars and communications antennas as well as other topside equipment and missiles, are quite vulnerable to the small fragments of an exploding shell. Since the CVT fuzes are designed only for surface targets, they do not need the high sensitivi-ties required of a fuze used against aircraft. Also the target’s velocity is negligible as far as its effect on signal processing is concerned. These factors make the fuze design for surface targets simpler, because the dynamic range of signal sensitivity and closing velocity are significantly reduced.

4-5.5.8.10.2. Environmental Considerations. The most frequently encountered and generally the largest source of unwanted background energy is the fuze’s own return signal from a water or land surface when the target is small and on the surface. Then it is necessary to discriminate between the signal returned from the target and that returned from the surface. A variety of techniques have been used, but none have completely solved the problem. Another source of unwanted energy is that radiated from both friendly and other transmit-ters, such as radars, navigational equipment, radio and television stations, jammers, communication links and a variety of other sources. Again, designs must either avoid operating on the same frequen-cies or find ways of countering the source. Envi-ronmental conditions also impose design requirements on the fuze. All parts of the fuze must be capable of being stored for long periods of time between the temperatures of -40°F and 160°F and still be completely operable between the tem-peratures of -20°F and +130°F. Rain drops striking the fuze radome during flight must not generate microphonic noise sufficient to prefunction the fuze. Entering clouds, where large electrostatic charges or lightning exists, must not cause prefunc-tion or damage the fuze either. Last, but not least, all fuzes must be safe to handle and use in the pres-ence of electromagnetic radiation hazards (RAD-HAZ) generated by shipboard or dockside electronic equipment.

4-5.5.8.10.3. Target Signal Generation. Figure 4-33 shows a vector diagram of a typical engage-ment between a fuzed projectile and a surface tar-get. The transmitter radiates an electomagnetic signal conforming to the relative amplitude and direction of the antenna pattern. An area of the surface directly below the projectile will intercept the transmitted energy and reflect back a portion of it, depending on the reflectivity of the surface. The Doppler signal is generated because of the relative motion between the fuze and the surface. As the height above the surface decreases, so that the two-way path length changes through an exact multiple of a half wavelength (λ/2) of the fuze transmitter frequency, the transmitted wave and the reflected wave are either in or out of phase. The two signals mix in the receiver circuit and are additive when in phase and subtractive when out of phase. After fil-

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tering out the RF component of the resulting sig-nal, the remaining low frequency peaks and nulls are the Doppler signal amplitude; the rate at which they occur is the Doppler signal frequency. The equation for the Doppler frequency is the same as for an air target engagement, where fd = VFcos θ/492. V is the axial velocity of the projec-tile in feet per second and fd is the Doppler fre-quency in Hertz. F is the frequency of the fuze transmitter in megaHertz, θ is the angle between the projectile velocity vector and the vertical, and 492 is a constant which relates the velocity in feet per second and the speed of light constant in meters per second with the two-way path length. The Doppler signal is in the audio frequency range and the transmitted signal is in the VHF or UHF range. In general, because the last several hundred feet of

projectile travel is at a nearly constant velocity, the Doppler frequency will also be nearly constant. The amplitude of the Doppler signal increases hyperbolically as the height above the surface decreases. In simple terms, this means each time the height decreases by a factor of two the signal amplitude increases by a factor of two. Most sur-faces are not flat and smooth and these irregulari-ties, such as waves on water or unevenness of the ground, with variations in its reflectivity brought about by such things as swamps, small lakes, rivers and trees, will produce a form of modulation of the Doppler signal with frequency components related to the horizontal velocity, Vh, of the projectile. This modulation is one form of noise that is unwanted.

Figure 4-33 Surface Target Engagement, Velocity Vector Diagram

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4-5.5.8.10.4. Target Burst Height Calculations . The burst height over flat surfaces can be calcu-lated for a simple fuze with linear circuits and a firing threshold from the equation, BH = 15' x O-sen x R x A/A-sen. Fifteen feet is the arbi-trary standardized height at which the O-sen is determined by the Navy. R is the surface reflectiv-ity, and A is the normalized value of the antenna voltage plot in the direction towards the surface. Figure 4-34 is a pictorial representation of the defi-nition of O-sen (oscillator sensitivity). The O-sen of a fuze is defined as the root-mean-square (rms) equivalent voltage of the peak-to-peak (p-p) volt-age of the envelope of the hyperbolic signal mea-sured at a height of 15 feet above an infinite plane with R and A having unity values. Amplifier sen-sitivity (A-sen) is defined as the rms voltage level of a sine wave having the same frequency as the Doppler frequency, which when suddenly applied to the input of the fuze signal processor, just causes the firing circuit to generate a trigger pulse. All

present fuze circuit designs have nonlinear circuits such as integrators or differentiators which are fre-quency and amplitude dependent. Fuzes with non-linear circuits will always have much lower burst heights than those calculated by the above equa-tion. The circuits cause a delay which varies with angle of fall of the projectile and the vertical com-ponent of the projectile’s velocity. The burst height varies also because of the modulation effects brought about by the surface irregularities mentioned above. For a group of fuzes these effects cause a dispersion of the burst height about a normal value. Additional dispersion occurs due to tolerances of the electronic components used in the fuze. Because of the hyperbolic nature of the buildup of the surface return signal, the burst height distribution of the fuze will actually be log-normal.

Figure 4-34 O-Sen Response Curves

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4-5.5.8.11. Circuit Design M728 and M732 Fuzes. Figure 4-35 and Figure 4-36 are block dia-grams of the M728 and M732 solid-state CVT-RF fuzes, respectively. In general, these fuzes transmit an RF signal and detect the small target return sig-nal. This small Doppler signal is amplified, fil-tered, rectified, integrated, differentiated and compared to a firing threshold, which generates a firing pulse to the electric primer. The frequency of these fuzes is in the ultra-high frequency (UHF) band. At these frequencies, antennas can be designed which are relatively efficient and small enough to fit in the front case of the fuze. This antenna system does not depend on the length of the projectile body as part of its antenna. Conse-quently, these fuzes can operate efficiently in all projectiles which have nose cavities that can hold them.

4-5.5.8.11.1. Transmitter-Receiver. The antenna, detector, oscillator and noise filter blocks shown in Figure 4-35 and Figure 4-36 contain the circuit components which perform the transmit-receive function of the fuze. The antenna forms a pattern typical of a longitudinal loop as shown in

the cross section view in Figure 4-37. The front of the metal amplifier body, which is grounded to the projectile, acts as the ground plane for the antenna.

4-5.5.8.11.1.1. Transmitter. The transmitter consists of an active electronic component, the transistor, and several passive components, such as resistors, capacitors and chokes used for proper biasing and feedback to sustain the oscillations, plus a PC loop antenna. Many of the capacitors and inductors are formed directly on the antenna loop. At these frequencies the circuit no longer resembles either a Hartley or a Colpitts oscillator, but a combination of both, because most of the components are formed by the stray capacitances and inductances of the transistor. The oscillator is designed and adjusted to operate in a controlled state of instability which allows it to change or react to a return signal from a nearby target. Oscil-lations begin when some transient noise voltage or current appears at the input to the transistor and is amplified to the point where enough energy is cou-pled back to the input through the feedback net-work to sustain the oscillation. The excess signal over that which is needed to barely sustain the over over that which is needed to barely sustain the oscillation is then emitted as the transmitted signal.

Figure 4-35 Fuze M728, Block Diagram

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Figure 4-36 Fuze M732, Block Diagram

Figure 4-37 M728 and M732 Fuze Radiation Pattern, Cross Section

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4-5.5.8.11.1.2. Receiver. The same antenna and oscillator components, along with one or more additional components, such as a diode detector, perform the receiver function for the fuze. The mixing of the return signal with the transmitted sig-nal effectively causes a change in the impedance of the antenna and thus the loading of the oscillator. This change is at a slow rate, and after rectification and filtering of the RF component, only the low frequency component, or Doppler, remains. The oscillator impedance is matched to the antenna impedance through the transformer action of the loop.

4-5.5.8.11.1.3. Noise Filter. The noise filter is used to reduce noise spikes that may occur in the RE voltage. It does not regulate the supply volt-age, but uses a Darlington amplifier to increase the effective value of a capacitor in what would other-wise be a simple RC filter. RE noise is attenuated by about 40 dB or a factor of 100. The noise filter functions for both the oscillator and the signal pro-cessor circuits.

4-5.5.8.11.2. M728 and M732 Fuze Signal Pro-cessors. The M728 and M732 fuze signal proces-sors amplify, integrate, differentiate and compare the threshold of the target return. They filter out and discriminate against unwanted background noise signals and then, at the optimum burst posi-tion, generate a firing pulse for the electric primer. These fuzes use all solid-state electronic compo-nents to perform these functions. The signal pro-cessing circuitry consists of the four blocks shown in Figure 4-35 and Figure 4-36 labeled as band-pass amplifier, integrator, differentiator, and firing circuit.

4-5.5.8.11.2.1. Band-Pass Amplifier. Band-pass amplifiers are used to amplify and pass on the tar-get signal to the next stage in the signal processor, which covers a narrow frequency band. They also minimize unwanted signals, such as microphonics, battery noise and wave noise, which generally cover a wider frequency band. Doppler frequen-cies are determined for the entire range of incom-ing projectile angles and velocities, and these frequencies primarily determine the upper and lower band-pass frequency limits of the amplifier. Microphonics help to determine the high frequency

end of the band as well as the slope. Wave noise partially to determines the low frequency end of the band and its slope. Battery noise is broad-band and partially determines the maximum amplifica-tion that the amplifier can have. The M728 and M732 fuzes have an advantage over the M513 and M514 fuzes because the solid-state components have significantly lower microphonics than vac-uum tubes. Also, the noise filter circuits eliminate much of the RE noise. Tubes and other older design components are very microphonic due to their large, inadequately supported electrodes. The edges of the band-pass are sloped at about 12 dB per octave. The burst height of different approach angles can be adjusted somewhat by making the slope steeper or shallower. This allows the fuze design to provide more optimal bursts to match the fragmentation pattern of the projectile. Generally, the lethality of a side-fragmenting projectile is optimum with higher burst heights at shallow angles of fall, and lower burst heights at steep angles of fall. The M728 and M732 amplifier band-pass is centered around the Doppler frequen-cies obtained at medium angles of fall, and the burst height is highest at these frequencies. At lower and higher angles, where the Doppler fre-quencies are at the band-edge, the burst height is less. This produces burst heights for the median and high approach angles essentially as needed. The low angle burst heights are not corrected prop-erly; however, the fuzes are seldom used at short ranges with shallow approach angles. The ampli-fier circuit is built as an integrated circuit chip. The circuit consists of a differential amplifier made with two Darlington amplifier input stages to obtain higher input impedances. The emitter resis-tance for the differential amplifier consists of a transistor, with its collector tied to the common emitters of the amplifier and its emitter tied to ground through a resistor. The base of the transis-tor has its bias controlled by two series diodes and a resistor shunted to ground. The diodes change voltage slightly with temperature and have a char-acteristic that compensates for the gain change of the amplifier. The output signal from the Darling-ton amplifier goes to the base of an emitter-fol-lower transistor. The emitter load of this stage consists of a fixed resistor in series with a comple-mentary pair of transistors connected to one of the terminals on the chip. The complementary pair is

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biased such that the signal out is clipped and appears as a half-wave rectifier (full-wave rectifier for M732) output signal which is fed to a shunt capacitor. The output impedance of the emitter cir-cuit is approximately 33K ohms which, in series with the capacitor, forms the integrator circuit (IC) for the fuze. The time constant of the integrator is approximately 16 milliseconds, which allows the integrator to function for signals above 60 Hertz. The discharge resistor for the integrator is also 33K ohms. One octave of high and low frequency filter-ing is accomplished at the input to the IC. Addi-tional band shaping is obtained with a feedback capacitor in the differential amplifier.

4-5.5.8.11.2.2. Integrator Circuit. The firing circuit will trigger any time its gate sees a voltage level that exceeds a certain threshold. Therefore, an integrator circuit is used to minimize the possi-bility of triggering the firing circuit because of sud-den sharp impulses of noise originating from such sources as microphonics, raindrop impacts and the RE. The noise impulses may have high voltage levels, but their duration is extremely short, hence they contain very little energy. A simple integrator circuit consists of a resistor-capacitor (r-c) divider in which the output signal appears across the capacitor. A capacitor needs a fixed energy input during a short period of time to build its voltage up sufficiently to reach the firing threshold. In the M728 and M732 fuze circuit, the integrator is formed from the output impedance of the emitter and an external capacitor connected between the emitter output and ground. The rectified Doppler signal from the emitter has both an ac and a dc sig-nal component. Most of the ac is bypassed to ground through the capacitor, but the dc compo-nent remains and charges the capacitor. This is the usable part of the signal. With a fixed integration time, the change in altitude at shallow angles is much less than at steep angles. This results in a smaller delay and consequently a higher burst height at the shallow approach angles than at the steep angles. This provides some compensation in burst height for side fragmenting projectiles, which benefit from higher bursts at shallow angles and lower bursts at high angles.

4-5.5.8.11.2.3. Differentiator Circuit. In the M728 and M732 fuze circuit, the integrator’s out-put voltage does not couple directly into the firing circuit, but first goes to a differentiator circuit. A simple differentiator circuit consists of a resistor-capacitor divider in which the output signal appears across the resistor. The M728 and M732 differentiator consists of a capacitor connected between the output of the integrator and the gate of the silicon-controlled rectifier (SCR), and a resistor from the SCR gate to the ground. The capacitor blocks out steady dc voltages but passes signals which are changing in amplitude above a certain rate. During a surface approach encounter, the amplitude of the signal builds up at a sufficiently fast rate during the last 100 feet of vertical travel to allow the integrated signal to be coupled through the differentiator capacitor. Because of the unique nature of the build-up of the surface approach sig-nal, the use of an integrator followed by a differen-tiator provides a very high level of discrimination against signals from any other source, particularly noise of a random nature. A differentiator circuit will also have a delay associated with its time con-stant which will be opposite to that of an integrator. At low Doppler frequencies the delay will be lon-ger than at high frequencies. The overall result will be that the combined delay for both circuits will be fairly constant over the entire Doppler fre-quency range.

4-5.5.8.11.2.4. M728 Firing Circuit. Figure 4-38 is a schematic of the M728 fuze firing circuit, including the CVT switching circuit. In normal use the CVT will be set between seven and 100 seconds (although markings on the fuze allow settings as low as five seconds), and the following sequence of events will occur. At time T = 0, when the gun is fired, setback and spin forces begin the arming process. In brief, the explosive train becomes aligned just beyond the end of the gun barrel, the RE begins to build up its voltage, and the RFSD clock starts to run. The RE voltage will be nearly completely up within several hundred milliseconds and two of the three firing capacitors will receive charge from the RE. The remainder of the fuze electronics does not receive power from the RE until later in flight, when switch S2 closes. These two capacitors charge through separate parallel paths. One path begins at the positive

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terminal of the RE, goes through R1, C1 and back to the negative end of the RE through the emitter resistor. The other begins at the positive terminal of the RE, goes through R2, C2 and back to the negative end of the RE through the current-limiting resistor shunting switch S1. Although charged, these capacitors cannot fire the electric primer until the RFSD clock allows S1 to operate and connect the electric primer into the circuit at a nominal 2.75 seconds of flight time. This action simultaneously removes the short from across the primer. From this time, and throughout the remainder of projectile flight, the primer can be fired any time a target or other solid object is impacted and switch S4 is closed. The MK 124 MOD 0 carbon bridge electric primer used in the M728 fuze is the same type used in the M513 and M514 fuzes, but the primer bridge resistance is restricted to a range of values between 2K and 5K ohms. When the M728 circuit was designed, the largest available capacitor with the smallest physical case size at a 30-volt rating was 1 microfarad. A single capacitor charged to 30 volts did not provide sufficient energy to initiate the primer. Two capacitors in parallel had sufficient energy, but due to the high primer resistance, the discharge time would be too long and the rate at which the available energy flowed through the primer could not assure that the primer would be ignited. The circuit which was ultimately used was one in which the firing capacitors were charged in parallel and discharged in series. This had the advantage of nearly doubling the voltage and at the same time halving the effective capacitance, thus reducing the discharge time. By using this circuit instead of two capacitors in parallel, the effective energy available increased about 2.25 times and the time needed to fire the primer was reduced by a factor of at least nine. The circuit works as follows: When the impact switch S4 is closed, the discharge current flows from ground through the primer, through C2, through Q1 from its collector to the emitter, through C1 and back to ground through the impact switch. In the proximity mode, the firing circuit works as follows: The turning capsule is set to the known

time of flight to the target (time to target, TT) or to an earlier time. The clock in the RFSD starts to run at T = 0, and at time to target minus 5 seconds (TT-5) a pellet is released from the switch ring. Centrifugal force from the spinning projectile presses the pellet against the two gold-plated pins (S2) extending from the rear of the power-supply outer can assembly. One of these two pins is connected to the ground end of the noise filter transistor’s base resistor. Once this resistor is grounded, the bias on the base is such that the noise filter circuit is turned on, which then allows the oscillator and signal processor to operate. As the clock continues to run, a second pellet is released from the switch ring assembly two seconds after the first pellet, at time TT-3. Centrifugal force also causes this pellet to be pressed against the lever, which is shown as S3 in the diagram. When S3 opens, it removes the short from capacitor C3. The capacitor charges up through the following path: The current flows from the positive end of the RE through the noise filter, then through R3, C3 and the emitter resistor back to the negative side of the RE. The SCR acts as a switch which operates when a sufficiently large target signal is encountered that produces a differentiated voltage pulse greater than the firing threshold of the SCR gate. The discharge path used to fire the electric primer when the SCR gate is triggered is as follows. When the SCR gate is triggered, the discharge current flows from ground through the primer, through C2, through Q1 from its collector to the emitter, through C3 and back to ground through the SCR. The current-limiting resistor is in series with switch S3 and prevents the primer from firing in case the switch contacts bounce. The shunting resistor across S1 is used in place of the electric primer during the fuze testing phase, and its value is set to limit the discharge current through Q1 and the SCR to a value that will not damage these components. Firing the electric primer initiates the rest of the explosive elements in the firing train, eventually setting off the main charge in the projectile.

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4-5.5.8.11.2.5. M732 Firing Circuit. Figure 4-39 is a schematic of the M732 fuze firing circuit. In normal use the CVT will be set between five and 150 seconds and the following sequence of events will occur. At time T = 0, when the gun is fired, setback and spin forces begin the arming process. The safing and arming device aligns the explosive train and enables the mechanical impact backup sliding detonator after a minimum safe separation distance corresponding to 25 to 38 turns of the projectile from the muzzle. The RE reaches full output voltage within several hundred milliseconds after firing and starts the electronic delay timer in operation. Approximately five to eight seconds before set time, depending on the set time, the electronic timer applies power to the monitor. The equation for calculating the proximity time is shown in Table 4-5. Charging of the noise filter capacitor (C9) in the monitor enables the electrical impact switch firing circuit. The noise filter output voltage charges the proximity mode firing

capacitor (C16) through resistors R17 and R18. The proximity mode firing circuit is not enabled, however, until the voltage on C16 reaches a value equal to the reference voltage established by the voltage divider formed by R22 and R23 (approximately two-thirds of the noise filter output voltage) causing the programmable unijunction transistor in series with the firing circuit to latch. This proximity circuit arming delay is 2 ± C.3 seconds. If, after the firing circuit is armed, the SCR is triggered by a suitable target signal, the detonator is fired by discharge of the firing capacitor through the unijunction transistor, the silicon-controlled rectifier, and the detonator bridge wire. (If the SCR is triggered before the circuit arms, the firing capacitor is safely discharged through the current-limiting resistor R18 and the charging cycle begins anew.) Should the proximity sensor fail, superquick PD function is provided by closure of the impact switch, which discharges the noise filter capacitor directly

Figure 4-38 Fuze M728 Firing and CVT Switching Circuit Schematic

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through the detonator. If the fuze electronics fails completely, impact backup is provided by the sliding detonator in the S&A rotor. Also shown in the . is a “telemeter” capacitor (C15) whose function is to momentarily reduce the noise filter output voltage when the SCR fires. The resultant output voltage shift causes an easily detected downward shift in the frequency of the fuze’s radiated signal. This feature permits checking for proper fuze action when test firings are conducted without any explosives being assembled within the fuze.

4-5.5.8.12. Modes of Operation of CVT Fuzes. Figure 4-40, Figure 4-41, and Figure 4-42 are developed views of the CVT fuze time setting scales; Table 4-6 and Table 4-7 explain the various features shown. In setting these fuzes, the follow-ing modes of operation should be observed:

4-5.5.8.12.1. VT-Only Mode Setting for M728 and M732 Fuzes. For proximity functioning, the fuze is set to a time that corresponds to the flight time to the target less several seconds. During flight, the M728 fuze will not respond to

proximity-sensed targets until approximately 2.6 seconds before the set time for all ranges. The M732 fuze will not respond to proximity-sensed targets until approximately three seconds before the set time for short times of flight and until approximately five seconds before the set time for long times of flight. To allow for ballistic errors, fuze timing tolerances, and tolerances on the estimated long time of flight, the fuze should be intentionally set to a time that is at least 10 seconds shorter than the estimated time of flight unless ECM conditions dictate otherwise. Setting the fuze for a time that is significantly shorter than the value stated above is also not recommended because the time of fuze broadcast is increased. Both the time that the fuze is exposed to ECM and the range of flight over friendly territory in which the fuze is in a proximity sensing and firing condition is thereby also increased. On the other hand, setting the fuze to a time that is approximately 50 seconds or more shorter than the time of flight may result in a proximity firing failure due to the expiration of battery life.

Figure 4-39 Fuze MK 732 Firing and CVT Switching Circuit Schematic

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Figure 4-40 Projected View of CVT Fuze M513A2/M514A1 Time Setting Scale (Shown Set at 20 Sec.)

Figure 4-41 Projected View of CVT Fuze M728 Time Setting Scale (Shown Set at 20 Sec.)

Figure 4-42 Projected View of CVT Fuze M732 Time Setting Scale (Shown Set at 20 Sec.)

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Table 4-5 M732 CVT Fuze Functions for Various Settings

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Table 4-6 M513/M514 CVT Fuze Functions for Various Settings

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Table 4-7 M728 CVT Fuze Functions for Various Settings

Table 4-8 Controlled Variable Time Fuze M728 Functions for Various Settings

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4-5.5.8.13. Proximity Sensing and Firing. When operating in the proximity mode, the elec-tronic timer switches power supply voltage to the oscillator, amplifier, and firing circuits 5 to 7 sec-onds before target time, depending on the time set. Voltage causes the oscillator to begin radiating an RF signal while the firing circuit is charging elec-trically. Approximately two seconds is required to reach the threshold voltage required to enable the firing circuit. As the fuze approaches the target, a return signal is received by the oscillator antenna and demodulated to obtain the Doppler signal, which is processed by the amplifier circuitry. When the required signal is received, the firing cir-cuitry is triggered and the electric detonator is initi-ated, detonating the explosive train, thereby functioning the projectile. If the fuze fails to sense the target in the proximity mode, an impact switch located in the amplifier circuit will close upon pro-jectile impact. An independent mechanical system is also available to automatically back up the impact switch; target impact causes the detonator in the S&A rotor to slide forward and impinge upon the firing pin, initiating the detonator.

4-5.5.8.14. Use.76mm, 62 caliber HE projectiles5-inch, HE and HI-FRAG projectiles

4-5.5.8.15. Physical Characteristics.Specification................................MIL-F-50596Drawing............................................. 11716451Weight ...........................................1.76 poundsLength .............................................5.97 inchesThread size ............................ 2.000-12UNS-lADiameter, max. ................................2.42 inchesIntrusion .........................................2.21 inches

4-5.5.8.16. Explosive Components.Electric detonator .....................Lead styphnate,

lead azide, and HMXStab detonator.................NOL 130 primer mix,

lead azide, and HMXLead..................................................... PBXN-5Booster ..................................................... CH-6

4-5.5.8.17. Arming.First safety Setback

No arm................................................800 g’s Arm .................................................1,300 g’sSecond safety Spin No arm............... 16.6 revolutions per second Arm ...................... 41 revolutions per secondOther safety

Electronic firing enables 7 seconds,maximum, prior to proximity setting.

Arming delayProjectile revolutions from muzzle .. 25, min

4-5.5.8.18. Operational Characteristics.Modes

Proximity................5- to 150-second setting;2 PD backups, mechanical

(sliding stab detonator) and electric (impact switch)

PD.......... mechanical (sliding stab detonator)Proximity timing

Turn-on time = 0.98 multiplied by (settime minus 5 seconds) + 2 seconds

Proximity firing enable time = Turn-on timeplus 2 seconds +0.3 second

Burst height (proximity)Over land..................................... 5 to 40 feetOver water ................................... 5 to 70 feet

Sensitivity (PD)All-fire.............. 2-inch plywood at 0 degrees

4-5.5.8.19. Packing.To loading depot ................... 8 fuzes/container:

21 pounds; 6 x 7.5 x 12 inchesFrom loading depot.......assembled to projectile

4-5.6. Variable Time-Infrared (VT-IR) Fuzes.

4-5.6.1. General. VT-IR fuzes currently in use by the U.S. Navy employ a passive sensing device that detects infrared radiation from the target’s hot exhaust gases and converts it into electrical pulses that stimulate the firing circuit. For proper opera-

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tion of the IR sensing device, a target that is a sig-nificant heat source is required. For this reason, the IR fuze is used primarily against jet aircraft, missiles, and other infrared radiating targets. IR fuzing offers a considerable improvement over the RF fuzes when used against jet aircraft because it optimizes the burst position for maximum lethality.

4-5.6.2. Background. The MK 91 and the MK 404 fuzes are passive infrared proximity fuzes used in the nose of 5" high explosive-loaded, frag-menting projectiles, respectively. See Figure C-6.The MK 404 fuze is also used in the 76mm guns.The MK 90 MOD 0 fuze was designed and released to production in 1961. The MK 92 MOD 0 (Figure C-7) and MK 91 MOD 0 fuzes were released to production in 1965 with improvements in the moisture sealing of the optics assembly and a redesigned signal processor. These changes were incorporated into the MK 90 MOD 1 fuze which was released to production in 1967. In l971, the fuze look angle was changed to provide improved burst position effectiveness for higher speed tar-gets. At the same time the optical lens material was changed from arsenic trisulfide to silicon, which is more rugged and less costly. The MK 91 MOD 1 contains these changes. In 1974, the MK 404 MOD 0 fuze was released to production for use with the 76 mm/62 gun. In 1975, it was certified for use in the 3"/50 gun and, in 1980, it was certified for use in the 5"/54 gun. Except for the passive infrared detector and its associated optical lens and window filter, which represented a major technological advance in projectile fuzing, the remainder of the fuze components are essen-tially the same as those used in the MK 73 fuze.

4-5.6.3. Design Features. The passive infrared fuze design provides a major advance in proximity-fuzed projectile antiaircraft effectiveness because it has accurately controlled burst positions, improved reliability, no degradation of effectiveness when fired low over waves, and is extremely immune to countermeasures.

4-5.6.4. Physical Description. All MK 90 series and MK 404 fuzes function fundamentally alike and contain the same basic components. The

MK 404 fuze differs from the MK 90 series in that it has an ABCA-standardized ogive, intrusion, thread and weight, and uses solid-state electronic components in its signal processor. The window filter and optics assembly are the same. The main components are: front case, window assembly, monitor (signal processor and firing control), reserve energizer, spacer block, rear fitting safety device, sleeve and steel diaphragm, and booster. Threads, intrusion lengths and weights differ because of projectile design differences.

4-5.6.4.1. Window Filter Assembly. The win-dow filter shown in Figure 4-43 consists of a syn-thetic sapphire window blank with an optical interference filter deposited on the back side and a thin mica sheet with an optical absorption filter deposited on the front side. Both pieces are cemented together with optical cement. The win-dow and two rubber gaskets, one above and one below the window, are placed in a recess in the top of the front case with a guard ring on top of them. The lip of the front case is then rolled over to crimp the assembly in place. Eposy is injected in a chan-nel in the front case around the window to provide a moisture seal. Synthetic sapphire is the only material which is strong enough to resist abrasive erosion from rain drops striking the window during projectile flight and is also optically transparent to infrared energy. The MK 90 and 91 window diam-eter is 0.787 inch. The MK 404 window diameter is 0.680 inch. The thickness of the sapphire is 0.100 and 0.081 inch respectively.

4-5.6.4.2. Front Case. The front case of the MK 404 fuze is a one piece metal construction. The metal parts of the front case are fabricated from cadmium plated steel to prevent corrosion. A channel with a fill and a vent hole is provided at two locations in the all metal front cases to allow epoxy to be injected to provide a moisture seal. One channel surrounds the window filter and the other channel is located at the interface between the top of the sleeve and the top of the front case internal threads.

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4-5.6.4.3. Optics Assembly. The optics assem-bly consists of a bullseye lens optically cemented to a glass substrate upon which the infrared detec-tor has been deposited. Figure 4-43 shows these two items. This cemented assembly is then placed into a mechanical package which ruggedizes and moisture proofs the detector. The lens material is arsenic trisulfide in the MK 90 MOD 0 and 1, MK 91 MOD 0 and MK 92 MOD 0 fuzes and sili-con in all the later developed fuzes. The detector is made by vacuum-depositing lead selinide over the substrate and then depositing a gold overlay which provides the detector pattern and the electrical con-nection to the four leads. The pattern of the detec-tor is circular with four equally spaced 50 degree segments connected in an electrical bridge arrange-ment.

4-5.6.4.3.1. Optics Assembly Package. Figure 4-44 shows a package which provides an improvedmoisture seal and is used on all IR fuzes except the MK 90 MOD 0. It consists of an inner cup made of lead placed around the side of the lens-detector assembly. A steel outer cup is placed over the lead cup from the top of the lens. The steel optics support is placed under the glass substrate. The steel crimp ring is placed around the outer cup and the optics support and then crimped with 1600 pounds force while the two end pieces are pressed together with 160 pounds force. A polyethylene pedestal is snapped into the optics support with the

detector leads emerging through holes in the pedestal. Epoxy is injected into the cavity between the bottom of the detector substrate and the pedestal thus moisture sealing the area of the optic assembly around the four leads. An additional moisture sealing step was added to the optics assembly on all IR fuzes manufactured after January 1971. The side and bottom of the lens-detector assembly is painted with a thin coating of a sealing material trade named “Glasshesive”. This provides an excellent seal by itself but, in addition, the mechanical package described above is also used.

4-5.6.4.4. Monitor. The monitor contains all the electronic subcomponents with most of them con-tained in an amplifier (shield) can. The impact switch and optics assembly are mounted on top of the can. The MK 90 MOD 0 fuze uses two shield cans to house the electronic components. The sec-ond can is called a firing control. For all fuzes except the MK 404 the individual components and the subminiature vacuum tubes are inserted into the top of a polyethylene bundle which provides proper shock support. The MK 404, fuze uses all solid-state electronic components which are mounted on two printed circuit boards. The boards are supported on the baseplate and properly spaced with heavy wire leads which also provide electrical circuit connections.

Figure 4-43 Optical Components of VT-IR Fuze, Exploded View

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4-5.6.4.5. Reserve Energizer. The Reserve Energizer (RE) is a dry-charged battery contained in a steel can, which plugs into the base of the monitor. The RE supplies the electrical power for the fuze circuitry. It also contains through leads to provide electrical connections for the firing pulse, the reed spin switch and the rear fitting safety device (RFSD) ground. The battery consists of a stack of electrode plates with appropriate insulators and spaces between each plate. The center of the stack is open and contains a glass ampule contain-ing an electrolyte fluid. Setback and projectile spin forces cause the glass to shatter and electrolyte to fill the spaces between the plates. The battery is potted with plastic material before being placed in its can. The can is crimped over the baseplate to hold the assembly together.

4-5.6.4.6. Temperature Compensating Net-work. The temperature compensating network used in the MK 90 MOD 0 fuze contains a thermis-tor that maintains optimum fuze sensitivity at tem-peratures from -20 to 105 degrees F by changing its value with varying temperatures. At 120 degrees F, however, fuze sensitivity is noticeably reduced. All the other IR fuzes have a similar network which controls the bias of the IR detector and works well over the entire temperature range of-20 to 130 degrees F.

4-5.6.4.7. Rear Fitting Safety Devices. The RFSD, shown in Figure 4-15, consists of laminated metallic disc sections that contain a clock assem-bly, a rotor assembly, electric detonator, a relay detonator, and a booster lead-in. It provides safety interlocks to prevent detonator initiation during handling, storage, and the safe arming period. In addition, the MK 90 series provides for self-destruction of undetonated projectiles at a predeter-mined point before end of flight in order to protect friendly ships or troops and to avoid stray dud rounds. This self-destruct feature was no longer required when MK 404 fuze was designed. The RFSD arms by removing a series of interlocks to permit the centrifugally operated rotor to rotate to the proper position. During the rotation the rotor breaks a shorting wire connected across the detona-tor. The safety interlocks prevent rotor rotation until the projectile is at a safe distance from the fir-ing gun. Subassemblies of the RFSD are described in Paragraph 4-5.1.4.5.

4-5.6.4.8. Fuze Booster. This is a steel cup filled with tetryl and protected by a thin aluminum cover. Newer fuzes use a CH-6 booster. It is located in the lower end of the fuze sleeve, below the RFSD. Initiation of the RFSD explosive train detonates the booster which in turn detonates the main charge in the projectile.

4-5.6.4.9. Assembly and Waterproofing. Assembly and waterproofing are accomplished as follows:

a. The window assembly is fitted into the fuze nose. The window rests upon a sealing ring that is supported by a shoulder in the fuze nose. Above the window is fitted another sealing ring followed by a locking ring. The assembly is held in compression by crimping the rim of the fuze nose against the locking ring.

b. The base of the optics and amplifier assembly is plugged into the reserve energizer which in turn plugs into the top of the RFSD. In some fuzes a spacer block is assembled between the reserve energizer and the RFSD. This subcom-ponent assembly is inserted into the upper end of the metal sleeve. The RFSD rests on a shoulder inside the sleeve. The sleeve is sealed near the bot-tom by a brazed diaphragm located just below the

Figure 4-44 Optics Assembly Package For All Other IR Fuzes

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lower surface of the RFSD. A stack of spacers is used as necessary to meet the capsule assembly requirements. Pressure to the stack is applied while the assembly is secured by crimping the sleeve lip over the amplifier flange. This forms the capsule assembly. The capsule is then screwed into the front case and tightened to a specified torque. The booster assembly is screwed into the back of the sleeve and torqued.

c. The sleeve diaphragm provides a seal at the bottom of the capsule assembly, and a gasket under the monitor flange seals the capsule assem-bly at the top. Epoxy is injected into the channel around the front case-sleeve interface and a chan-nel around the window-filter to moisture seal these areas.

d. Earlier fuzes, such as the MK 90 MOD 0, have a sleeve which does not use a diaphragm; thus, the fuze component assembly is handled dif-ferently. The monitor, fire control (when used), reserve energizer, and RFSD are plugged together and then placed into a front case. The sleeve is placed over the assembled components and screwed into the front case with the specified torque. Stack pressure is applied to the bottom of the RFSD, and a holding ring is simultaneously tightened. The booster assembly is screwed into the inner thread of the holding ring. A waterproof-ing gasket and another holding ring are placed around the booster and tightened with the required torque to provide the rear moisture seal. Sealing at the front case-sleeve interface is by a gasket between the threaded insert shoulder and the upper edge of the sleeve. The fuze nose is sealed by seal-ing rings on each side of the window assembly held in compression by the crimped rim of the nose.

4-5.6.4.10. Operation. The operation of the VT-IR fuze is similar to that of the VT-RF. The VT-IR fuze is designed to operate automatically at a point of optimum lethality or upon impact with the tar-get. It also operates to self-destruct in the event the target is missed (self destruct feature is not present in the MK 404). The fuze has two main functions: safe handling and arming and detonation of the main charge within the target burst area. When a VT-IR fuze projectile is fired, setback and centrifu-gal forces initiate the arming sequence. Electrical and mechanical safety interlocks are removed to

arm the fuze. When near a hot target, the fuze opti-cal system admits infrared radiation that is con-verted into electric pulses. The pulses are amplified and utilized to discharge a capacitor through an electric detonator. Detonation of the detonator initiates the explosive train, thereby set-ting off the main charge of the projectile. At shal-low trajectories, if VT action does not occur prior to impact, a switch in the fuze closes and fires the detonator at impact. Self-destruct action (when provided) occurs after the projectile spin decays sufficiently to permit a reed spin switch (Figure 4-16) to close the firing circuit.

4-5.6.4.11. Safety Features. VT-IR fuzes are among the safest fuzes in the U.S. Navy. Many design features are provided to ensure safe handling, safety in the bore, and freedom from muzzle bursts. Rough handling may cause damage, resulting in abnormal operation or duds, but it is improbable that such treatment is hazardous. A severe blow to the fuze (such as dropping the fuzed projectile) does not reduce safety but may decrease operability and may even render the fuze a dud if the battery ampule is shattered. If dropping occurs within 1 minute before loading the gun and firing, the round has a high probability of operating normally. After 1 minute the round is still safe to fire, but reliability degrades rapidly with time because of the short battery life after activation. Components contributing toward safety of the VT-IR fuze are the reserve energizer, the charging resistor, the setback pin, the clock-controlled detonator unshorting wire, the out-of-line rotor, and, when used, the reed spin switch. The features of these components have been described in the preceding paragraphs.

4-5.6.4.12. Spacer Block. The spacer block is a molded plastic cylinder with most of its center hollowed out. The top surface is left intact and thick enough to provide support for the RE baseplate. The hollow section reduces the weight of the spacer block on the RFSD and at the same time distributes the weight to the outer wall of the RFSD which is better suited to support the weight during setback. The height of the spacer varies with the fuze in which it is used. Some fuzes do

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not need a spacer at all. Three floating pins provide electrical connections through the spacer between the base of the RE and the RFSD.

4-5.6.4.13. Sleeve. The steel sleeve encloses the fuze components and screws into the front case. It is strong enough to support the weight of all the components during the periods of extremely high setback forces. Earlier fuzes such as the MK 90 MOD 0 do not contain a steel diaphragm in the sleeve. These fuzes required holding rings and a waterproofing gasket. Sleeves used in later fuzes have a brazed or laser welded diaphragm located just below the surface of the rear fitting to provide a moisture seal.

4-5.6.5. Functional Description and Theory of Operation. This section is primarily for those individuals who have some knowledge of electro-optical circuitry or seek a more detailed explana-tion of the theory of operation of infrared fuzes. The process by which each component performs its task and how these tasks combine to perform as a fuze is described.

4-5.6.6. Design Considerations. The design of an optical system for a passive infrared proximity fuze is determined primarily by consideration of the expected spectral character of the target and its background radiation. The fuze should be capable of discriminating between these two radiating sources.

4-5.6.6.1. Target Energy Considerations. For fuzing applications involving head-on target aspects, the only significant source of infrared energy is from the hot gases in the target's exhaust plume. The energy radiated by these gases is entirely selective and falls primarily in two bands. One at a wavelength of 2.7 microns, due to the emission of hot water (H20) vapor, and one at 4.3 microns, due to the emission of hot carbon dioxide (CO2) gas, which has about ten times greater energy content than the H20 vapor. On the basis of available target energy then, one would select the CO2 emission as the proper band for fuze opera-tion. However, the difference in energy in the two bands is more than offset by the difference in sensi-tivity of available detectors. Lead sulfide (PbS) detectors, with good sensitivity out to 3.0 microns,

are suitable for use in the H2O emission band; but, in the longer wavelength CO2 band, the lead sele-nide (PbSe) detector with sensitivity out to 5.0 microns is the logical choice. The PbS detector is about two orders of magnitude more sensitive in the H2O band than the PbSe is in the CO2 band. Therefore, the signal-to-noise ratio (S/N) for a PbS system operating in the H2O band is expected to be about ten times greater than for a PbSe system operating in the CO2 band. On the basis of target signal alone, the PbS system would offer a consid-erable advantage.

4-5.6.6.2. Background Energy Considerations. In order to achieve the ultimate in operability, the fuze must be capable of functioning on the target energy in the presence of all natural background sources such as solar radiation and reflections from clouds and water. The instensity of radiation is by far the greatest from direct sunlight, the sun being approximated by a 6000oK black body. Now the advantage of operation in the 4.3 micron CO2 band becomes apparent if we consider the solar radiation curve shown in Figure 4-45. At sea level the atmosphere is completely opaque to solar radiation in both absorption bands, but at 17,000 feet, where these measurements were taken, the 2.7 micron band is no longer completely absorbing and, in fact, the radiation from the sun is appreciably greater than from the target. On the other hand, the CO2 band is still completely opaque at 17,000 feet and remains opaque to altitudes well above 40,000 feet. Furthermore, the width of the bottom of the H2O absorption band is only about 0.1 microns as compared to about 0.2 microns for the CO2 band, thus making the simple filter discrimination problem more difficult in the shorter wavelength band. Therefore, a simple filter would theoretically provide absolute discrimination between the target and the sun in the CO2 band but would be completely inadequate in the H2O band. For the short target ranges involved in projectile fuzing applications, the atmospheric attenuation of target emission is still small enough to allow sufficient energy for fuze stimulation in either band. Figure 4-45 also shows the target energy to be expected for a miss distance of 40 feet, a look

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angle of 38.5 degrees and an altitude of 15,000 feet in both bands. The CO2 band was selected for the fuze design.

4-5.6.7. Optical Components. The optical system consists of essentially three parts; a band-pass filter for isolating target energy within the atmospheric absorption band, a thick lens for gath-ering and focusing target energy, and a detector which is optically cemented to the rear surface of the lens. The detector is made up of four 50° annu-lar sectors connected electrically to form a bridge circuit. The lens-detector system is designed so that the field-of-view seen by the four segments of the detector is composed of four sections of a cone whose half-apex angle corresponds to the desired look angle. The electrical signal generated by the detector then consists of a series of 50° pulses or 55% duty cycle caused by the rotation of the pro-jectile. Figure 4-46 shows the optical components layout with a simplified ray trace depicting the look angle and the beam width. A top view of the detector pattern and a table listing the look angle for the various IR fuze MKs and MODs is also shown in the figure.

4-5.6.7.1. Window Filter. The window filter acts as an optical bandpass filter for infrared energy. The interference filter is vacuum-depos-ited on the back of the synthetic sapphire window blank and consists of alternate 1/4 wavelength (λ) thick layers of germanium and silicon monoxide. The interference filter allows a narrow band of energy to pass. Because it also passes energy in shorter harmonic wavelengths of the primary band, an absorption filter consisting of lead telluride, which is vacuum-deposited on the front of a mica disc, is needed to eliminate these shorter wave-lengths. The two pieces of the filter are then cemented together with optical cement with the active filter surfaces in contact with each other. This arrangement protects the filter from scratches ad humidity. The individual filter response curves and a curve of relative detector response are shown in Figure 4-47. The composite response curve of the window filter in Figure 4-48 shows the enhancement of the target signal compared to the sun signal.

Figure 4-45 Solar and Target Radiation vs. Wavelength

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4-5.6.7.2. Bullseye Lens. The function of the lens is to collect and focus the infrared energy on the detector. The lens material in the original design was arsenci trisulfide (As2S3); but, because it was imported and somewhat fragile, it was later abandoned when less expensive transistor grade silicon (Si) became available. Silicon is very rug-ged and a simple steam process can be used to form an antireflection coating of silicon monoxide (SiO). The lens is approximately 0.5 inch long and 0.5 inch in diameter. Si has good transmission properties out to 6 microns.

4-5.6.7.3. Detector. The detector functions as a transducer and converts infrared energy into elec-trical energy. The detector material is chemically deposited PbSe operating at ambient tempera-tures. PbSe is a photoconductive material. When infrared energy is focused on the PbSe, the electri-cal resistance of the detector decreases. Since the detector is in an electrical bridge configuration, any change in the resistance of one detector leg causes an unbalance in the dc voltage divider action of the bridge. This change occurs rapidly enough to allow the signal to be capacitively cou-pled to the preamplifier stage.

4-5.6.7.3.1. Dectector Variables. The detector presents several unique problems when studied as a signal generator. The resistance of the detector at +75°F can range from 0.4 to 4.0 megohms with present specifications. The resistance is lowered by a factor of two at +120°F and increased by a factor of three at -20oF, hence the resistance may vary from 0.2 to 12 megohms. The amplifier is connected to the bridge detector and thus will see impedances which will vary between 0.1 and 6.0 megohms, a 60 to 1 variation in generator imped-ance. The IR sensitivity (S1) of the detector at +75°F may range from 1.3 to 3.3 cm2/w with pres-ent specifications. The signal output of the detec-tor is down by a factor of three at +120°F and up by a factor of ten at -20°F. Therefore, the signal output varies through a ratio of 75 to 1 within the temperature specification. A thermistor-controlled detector bias network maximizes the S/N of the detector and limits the signal variations over the temperature range to approximately a two-to-one ratio.

Figure 4-46 Optical Components, Detector Pattern, and Look Angles for all VT-IR Fuzes

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Figure 4-47 Window Filter and Detector Response Curves for VT-IR Fuzes

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4-5.6.7.3.2. Dectector Configuration Advan-tages. The four terminal bridge circuit of the IR detector offers a three-fold advantage. In a bal-anced bridge network the bias supply noise will be canceled out. Secondly, in conjunction with the amplifier, it offers twice the normal electrical out-put for the same target energy level, as no external load resistor is required for the detector. Thirdly, it acts as a frequency doubler, which allows a two-fold increase in the S/N, because detector noise decreases in inverse proportion to the frequency.

4-5.6.7.3.3. Dectector Output Signal. The envelope of the detector output signal is related to the effective length of the target exhaust plume, the temperature of the exhaust plume, the fuze look angle and the beam width of the look angle. The individual pulses generated within the envelope of the output signal are related to the projectile spin, the duty cycle of the detector and the diameter of the targets exhaust plume. Figure 4-49 shows cal-

culated envelopes of the signature of a single J48 jet engine in an F9F aircraft at four miss distances. This target is used as the standard-test target for the testing of all IR fuzes. The specific parameters of each envelope are given in the figure. The 20-foot miss-distance envelope also shows the individual pulses generated by the detector, which forms the envelope. One pulse is generated for each segment of the detector. A signal is generated in the follow-ing way, using as an example, an IR-fuzed projec-tile on a parallel path with a target at a miss distance (MD) of 20 feet. The fuze could be ori-ented such that the detector segment which first senses the target energy would generate a low-level-positive going signal. As the projectile spins and moves further past the target, the signal increases rapidly but eventually returns to the noise level of the detector when the segment ends. Shortly thereafter the next detector segment is looking at the target exhaust and the generation of a negative-going signal begins, which is still higher

Figure 4-48 Calculated Detector Output Signals for VT-IR Fuzes

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in amplitude because shading effects of the target tail pipe are minimized and the middle of the beamwidth of the detector is approaching. Thus one full cycle of a signal has been generated for only half a revolution of the projectile. In effect the frequency of the signal was doubled with respect to projectile-spin rate. The next cycles are generated in the same fashion, eventually produc-ing the remaining pulses shown within the enve-lope. The amplitude of the pulses slowly diminishes because the exhaust gas cools further back in the plume.

4-5.6.8. Signal Processor. The function of the signal processor is to amplify, integrate and com-pare the threshold of the signal, filter and discrimi-nate against unwanted background noise and generate a firing pulse for the electric detonator. All IR fuzes perform these functions, but the cir-cuitry of the MK 90-series fuzes, which use vac-uum tubes, is quite different from the MK 404 fuze, which uses all solid-state electronic compo-nents. Both signal processors are described below.

Figure 4-49 Detector Signal Envelopes at Selected Radial Miss Distances

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4-5.6.8.1. MK 90-Series Fuze Signal Processor.4-5.6.8.1.1. Differential Amplifier. Figure 4-50 is a block diagram representative of the MK 90-series of fuzes. Stages V1 and V2 form the differ-ential amplifier. The vacuum tube triode (V1) in the first stage and its associated components receive the detector signal and noise from one half of the bridge network. This signal and noise is amplified approximately 20 times, inverted, divided down and added to the input of the second stage triode (V2) at approximately a unity gain level. The detector signal and noise from the other half of the bridge also appears at the input of V2. These signals appear alternately as only one half of the detector bridge generates a signal at one time. The noise from the power supply is nearly equal and in phase at both outputs of the detector bridge. Since one of the outputs is inverted, the noise effectively cancels out at the V2 input. The remaining detector noise, which is not canceled, and the composite detector signal are amplified in V2 by a factor of 20.

4-5.6.8.1.2. Band Pass Amplifier. Stages V3 and V4 provide most of the band pass filtering for the fuze. V3 has a negative feedback circuit which limits the gain to six and provides good gain stabil-ity. The resistors and capacitors at both the input and output of V3 form a high pass and a low pass filter network which have attenuations of six dB/octave. V4, the only pentode in the fuze circuit, has a gain of 20. Its associated components also provide the same high and low pass filtering as V3. The result is a band pass amplifier with a net gain of 120 centered at 500 Hz and high and low pass filtering of 12 dB/octave. The gain of the entire circuit including the differential amplifier is 2400. Any signal appearing on the screen grid of V4 is rectified, filtered and fed back to its control grid as a negative dc voltage, to form an automatic gain control (AGC) circuit. The time constant of the AGC circuit is long enough to prevent fast rising target signals from affecting the gain, but short enough to allow AGC response to persistent unwanted signals such as detector or battery noise or possible sun signals. The AGC response is then used to reduce the gain of V4 sufficient to prevent prefunctioning on the unwanted signals.

Figure 4-50 MK 90-Series Fuze-Block Diagram

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4-5.6.8.1.3. Rectifier, Integrator and Sun Dis-criminator. Immediately following the pentode stage is a diode clamping and voltage doubling cir-cuit. The output of this circuit is a positive going series of pulses clamped at -7.5 volts. This signal is fed to the resistance-capacitance (RC) integrator circuit which smooths the pulses and generates a positive going envelope. If this envelope is slow rising, as it will be in the presence of a sun signal, the resistive divider circuit following the integrator will attenuate the envelope to about 45% of its input value. If the rate of rise of the envelope is fast, as it will be with a target signal, then a capaci-tor shunting the top resistor in the divider will pass the envelope with negligible attenuation. The volt-age output of this divider is fed to the input of V5, the thyratron firing stage. Its grid is also biased at -7.5 volts and any time the signal, which is a posi-tive voltage, reduces the negative bias to a value of about -2.0 volts, the thyratron will fire.

4-5.6.8.1.4. Firing Circuit. Figure 4-51 shows a diagram of the firing circuit, including the electric detonator and its shorting wire, the reed spin switch, the impact switch and the RE power sup-ply. All MODs of the MK 90-series fuzes incorpo-rate both the reed spin and the impact switches. Gun firing generates two independent forces within the fuze. The setback force during projectile accel-eration in the gun barrel breaks the glass ampule of the RE and depresses the setback pin of the RFSD,

thus unlocking the clock timing mechanism. The spin force causes the electrolyte to fill the spaces between the dry charged cells of the RE, unlocks the rotor detents and provides drive for the clock timing mechanism. After the spin reaches a preset value, centrifugal force opens the reed spin switch thus removing the short across the firing capaci-tor. When the clock has run for approximately 0.4 seconds, the rotor of the RFSD is unlocked. The unbalanced rotor, with an out-of-line explosive lead, then rotates due to centrifugal force to align the explosive lead. Just before full-rotor alignment occurs, the shorting wire across the electric detona-tor is broken by a pin in the rotor. During this interval, the RE voltages also rise to approximately 95% of their full values within the first 0.1 seconds (at room temperature). As the RE voltages build up, the 100-volt supply is applied to the firing capacitor through the charging resistor. The capac-itor stores electrical energy and provides a very low impedance path to dump the energy through the electric detonator when needed. The rate of charge to the firing capacitor is deliberately kept low to prevent the accumulation of sufficient energy in the firing circuit to fire the detonator before the projectile has traveled at least 200 feet from the gun (safe separation). This RC delay pro-vides a backup safety feature in the remote case of a clock failure. The RFSD is the primary safety device in the fuze. Its carbon bridge electric deto-nator has an impedance of 0.7K to 15K ohms.

Figure 4-51 MK 90 Series Firing Circuit Schematic

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4-5.6.8.2. MK 404 Fuze Signal Processor.

4-5.6.8.2.1. Differential Amplifier. Figure 4-52 is a block diagram of the signal processing cir-cuitry. The amplifier is one half of an integrated circuit (IC) operational amplifier (Op Amp) which has a differential input that sums the detector out-put signals. The Op Amp has a single-ended out-put and a gain of 20. This stage essentially duplicates the two-tube differential amplifier used in the MK 90-series of fuzes.

4-5.6.8.2.2. Coherent Detector. A unique solid-state coherent detector has been developed for demodulating the IR detector signals. This mono-

lithic phase locked loop (PLL) and detector system exhibits a high degree of frequency selectivity, and, due to its coherent nature, it offers a higher degree of noise immunity than noncoherent peak detection demodulators. The basic concept of a PLL system has been known since the early 1930s. However, because of the high cost and complexity of PLL system designs, applications have been limited to precision measurements requiring a high degree of noise immunity and very narrow bandwidths. The availability of a low cost, microelectronic, mini-dip (dual in-line package) PLL makes possible new applications which cost and complexity previously precluded.

Figure 4-52 Fuze MK 404, Block Diagram

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4-5.6.8.2.3. Phase Locked Loop Operation. The PLL is a frequency-feedback system consisting of a phase comparator, a low pass filter, an error amplifier in the forward path and a voltage controlled oscillator (VCO) in the feedback path. When no signal is present, the error voltage is equal to zero. Then the VCO operates at a preset frequency, fo, the free running frequency. When an input signal fs, close to fo is present, its phase and that of the VCO are compared in the phase detector. fo is a beat note whose frequency is equal to the frequency difference of fs and fo. This signal is filtered in the low pass filter to develop a control voltage which drives the VCO frequency in a direction tending to decrease the phase error. When the input and VCO frequencies are the same, this phase difference assumes a small constant value and the loop is said to be “in lock”. The corrective action of the feedback is such that once the loop locks up, the VCO will follow changes in the input frequency to provide a clean frequency reference in step with the input signal. The output of the differential amplifier splits, one half going to the PLL and the other half going to a phase detector which is modulated by the output of the PLL. Whenever the two inputs to the phase

detector are synchronized, there is an output signal from the phase detector. This output is filtered by the envelope detector and integrator and eventually reaches a threshold level that operates a comparator circuit. The step function output of the comparator provides the trigger pulse for the gate of the silicon controlled rectifier (SCR).

4-5.6.8.2.4. Firing Circuit. Figure 4-53 is a schematic diagram of the firing circuit, including the electric detonator and its shorting wire, the impact switch and the RE power supply. The MK 404 fuze does not contain a reed spin switch. The circuitry operates the same as that of the MK 90-series of fuzes. The SCR performs the identical function of the thyratron and behaves like a shorting switch when its gate is biased on. In this circuit, the RE voltage has a nominal value of 30 volts and the electric detonator has an impedance of 3 to 7 ohms. The same safety features are incor-porated into this fuze as in the MK 90-series. Because the electric detonator has a very low impedance and requires approximately 10 times more energy to fire than the carbon bridge detona-tors of the MK 90-series fuzes, this fuze design has an improved handling safety, particularly during manufacture.

Figure 4-53 Fuze MK 404, Firing Circuit Diagram

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4-5.6.8.3. Modes of Operation of Firing Cir-cuit of MK 90-Series and MK 404 Fuzes. Dur-ing normal operating conditions the fuze firing cir-cuit will be completely charged and armed after approximately 0.4 + 0.1 seconds of flight. The fuze will remain in this condition until such time as one of the following events occurs:

a. The fuze encounters a target and the firing circuit is triggered as described in paragraph 4-5.6.8.3.

b. The fuze impacts the target and the impact switch is crushed. This action performs the same shorting function as the thyratron or SCR. The rest of the action is the same as described above.

c. No target is encountered. The projectile will continue its flight, if fired at a sufficiently high quadrant elevation (QE), until the normal spin decay allows the reed spin switch to reclose if the fuze contains a reed spin switch. This switch pro-vides the same shorting function as the impact switch or the thyratron and SCR. That is, it dis-charges the firing capacitor to initiate the firing train’s electric detonator and self-destructs the pro-jectile in flight. This switch is designed to close at a range exceeding 10,000 yards or 20 seconds of flight time minimum. If no reed spin switch is present or if the QE is below that which allows SD action, the impact switch will close on contact with water or land and detonate the projectile.

4-5.7. Fuze MK 91 (Variable Time-Infrared).

4-5.7.1. General. MOD 0 is superseded by MOD 1. All of the MK 91 VT-IR fuzes have the self-destruct feature and are of the vacuum tube design.

4-5.7.2. Description. The exterior views of MK 91 fuze are shown in Figure 4-54. The exterior surfaces of the fuze are of plated metal except the recessed window. A highly efficient sun rejection feature is utilized in the fuze which practically nullifies the effects of the sun as a potential “target.” A unique moisture sealing method is used to protect the moisture-sensitive detector. The fire control circuit is contained in the fuze monitor. The MOD 0 and MOD 1 fuzes are essentially the same, except that the MOD 1 fuze incorporates a

silicon lens rather than the arsenic trisulfide type used in the MOD 0, and that permits direct contact of the wax film with the air stream. Upon gun firing, minute particles from propellant gas blow-by are deposited upon this wax film. This wax protective coating is then removed along with these deposits early in the projectile flight by the effects of aerodynamic heating and centrifugal force. The sleeve is plated steel with a steel booster cup in the annular cavity. A highly efficient sun rejection feature is utilized in the fuze that practically nullifies the effects of the sun. A unique moisture sealing method is used to protect the moisture sensitive detector. The fire control circuit is contained in the fuze monitor. The MOD 0 and MOD 1 fuzes are essentially the same except that the MOD 1 fuze incorporates a silicon lens rather than the arsenic trisulfide type used in the MOD 0 and the look angle has been changed. The MOD 0 fuze is useful for firing exercises, having the same reliability as the MOD 1 fuze, and was designed to be effective for use against targets with speeds up to Mach 0.9. The MOD 1 fuze has been optimized to work against targets at all speeds up to and greater than the MOD 0 fuze.

4-5.7.3. Handling and Loading. Protection of the fuze window is provided by the waterproof pro-tective cap. Care should be exercised after removal of the waterproof protective cap to ensure that the fuze window is kept clean.

4-5.7.4. Use.5-inch, HE-IR projectiles


Specification....................................WS 1996Drawing............................................2501729Length ......................................... 9.33 inchesIntrusion ...................................... 5.09 inchesMaximum diameter ..................... 2.73 inchesSleeve diameter ........................... 2.00 inchesThread size ........................ 2.350-10UNS-2AThread length ..................................0.71 inch

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4-5.7.6. Fuze Components.Monitor

MK 91 MOD 0...................... MK 22 MOD 0MK 91 MOD 1...................... MK 29 MOD 0

Reserve energizer ..................... MK 25 MOD 0RFSD........................................ MK 18 MOD 7 Electric detonator.........MK 63, MOD 0; lead

styphnate, lead azide, PETN Rotor detonator ... MK 64 MOD 0, lead azide Booster lead-in......................................TetrylBooster .................. MK 30 MOD 0; tetryl lead,

tetryl booster


No arm................................................ 900 g's All arm ............................................ 1,385 g'sSpin

No arm.................. 40 revolutions per second All arm ............................... 780 to 1,300 feet

4-5.7.8. Function.Type ....................... Proximity airburst, impact,

self-destructDelay............................................Instantaneous

4-5.7.9. Packing. MK 91 MODs 0 and 1: 540/pallet (18 subgroups of 30); 41 cubic feet; 2,067 pounds (estimated gross weight).

4-5.8. Fuze MK 404 0, 1 and 2 (Variable Time Infrared).

4-5.8.1. General. The MK 404 0 and 1 fuzes (Figure 4-55) are short-intrusion, solid-state versions of the MK 90 series of passive infrared fuzes. They have no self-destruct feature. These passive infrared fuzes provide virtual immunity to countermeasures and unimpaired effectiveness over water. The MK 404 is capable of functioning near hot targets (jets or missiles) and contains a backup impact feature capable of functioning on water or 0.04-inch-thick aluminum. The fuze contains an RFSD that provides an arming distance of 700 to 1,400 feet from gun muzzle depending on projectile caliber. It has been demonstrated that MK 404 fuze does not fire prior to completion of its primary (mechanical) and secondary (electrical) arming times. These fuzes conform to the MIL-STD-333 configuration for new short intrusion nose fuzes with boosters, 75mm and larger. The fuze is composed of two major assemblies; a front case assembly and a capsule assembly screwed together and pinned at the threaded intersection and then sealed with epoxy at the interface. The front case assembly consists of a sapphire window, a filter sealed with epoxy, and a steel front case. The fuze assembly consists of a steel sleeve, with a diaphragm brazed in the lower end, and a front case assembly, which together enclose the solid-state monitor, the reserve energizer, and the RFSD. An 11.0-gram charge booster is screwed into the

Figure 4-54 Fuze MK 91 (Variable Time-Infrared), Cutaway View

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rear of the sleeve below the diaphragm with an O-ring seal. The MOD 1 has improved signal processing, which uses a low-voltage vice high-voltage reserve energizer. Also the MOD 1 has improved sealing of the optics. The MOD 2 changed the electronics from discrete components to surface mount components with a semi-custom ASIC. The new electronics use an instrumentation amplifier in the ASIC for amplification only, as compared to the previous MK 46 MOD 0 Monitor which uses a single op amp for both filtering and gain. Consequently, lower value input resistors are used permitting implementation in a linear array and eliminating the need for circuit shielding. The new electronics draws less current than the previous monitor, 9mA as opposed to 25 to 40mA. The new monitor will perform in the same manner as the old monitor and will therefore have the same operational field performance. The new monitor has improved noise immunity which may improve its performance in the field.

4-5.8.2. Handling and Loading.

A THIN WAX COATING (TAN IN COLOR) IS APPLIED AT THE FAC-TORY TO THE FUZE WINDOW MOUNTED ON THE END OF THE NOSE OF FUZE MK 404. THIS WAX COATING PROVIDES PROTECTION FROM THE DEPOSITION OF RESI-DUE FROM BLOW-BY GASES DUR-ING FIRING FROM GUN AND MUST NOT BE REMOVED.

Protection of the fuze window is provided in shipment by the cartridge tank. Upon removal of the round from this container, care should be exercised to ensure that the wax coating is kept clean and not damaged. In general, the effects of aerodynamic heating and spin after gun firing remove any foreign matter that may have been accidentally deposited on or trapped in this wax coating during shipboard handling of the exposed round.

4-5.8.3. Use.5-inch, HE-IR, HI-FRAG, and Puff projectiles76mm, 62 caliber HE-IR projectiles



MOD 1Specification..................................WS 19611

Drawing............................................5178357MOD 2


AllWeight with booster ................... 2.10 pounds

Length (overall)............................. 5.7 inches Intrusion ...................................... 2.21 inches Maximum diameter ..................... 2.40 inches Sleeve diameter ........................... 1.75 inches

Figure 4-55 Fuze MK 404 MODs 0 and 1 (Variable Time-Infrared), Cutaway View

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Thread size...........................2.000-12UN-2A Thread length .................................. 0.90 inch

4-5.8.5. Fuze Components.MOD 0

Monitor ................................. MK 40 MOD 0 Reserve energizer.................. MK 40 MOD 0MOD 1

Monitor ................................. MK 46 MOD 0 Reserve energizer.................. MK 43 MOD 0MOD 2

Monitor ................................. MK 46 MOD 1Reserve energizer.................. MK 43 MOD 0

AllRFSD .................................... MK 42 MOD 3

Electric detonator . MK 71, MOD 0; n-leadstyphnate, lead azide, PETN

Rotor detonator ... MK 64 MOD 0; lead azideBooster lead-in

Early MOD 0 ........................................Tetryl Later MOD 0 and all MOD 1& 2 .... PBXN-5 Booster assembly (Drawing 5468148) ..CH-6


No arm................................................900 g’s All arm ............................................1,385 g’sSpin

No arm.................. 40 revolutions per secondAll arm ............... 145 revolutions per second

Arming distance76mm,

62 caliber .......................... 700 to 1,330 feet 5-inch................................ 780 to 1,400 feet

4-5.8.7. Function.Type ........................ Proximity airburst, impactDelay............................................Instantaneous


4-6. MULTIPLE FUNCTION FUZES

4-6.1. MK 419 Multi-Function Fuze.

4-6.1.1. General. MFF provides the Fleet with a state-of-the art, RF based, all-purpose fuze that maximizes mission flexibility and magazine effec-tiveness. See Figure 4-56 and Figure C-21.

Figure 4-56 Multi-Function Radio Frequency Fuze

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4-6.1.2. Background. The basic design for MFF was established in the late 1980s. Currently, the MFF is only used on 5-inch ammunition. The only way to set MFF in an operational environment is via the MK 34 Fuze Setter, which is part of the MK 45 gun mount. Only the 5-inch guns have inductive setters. The fuze default mode is Autonomous (AUT). The AUT mode attempts to engage an air or point target during the first 10 seconds of flight, then switches to surface mode with the height of burst set to detonate 25 feet above the surface (land or water). The MFF capability includes all modes of opera-tion, except PD delay, so that MFF could eventu-ally replace most existing fuzes and simplify the Navy's projectile inventory.

The MFF is set automatically by the gun con-trol system via the MK 34 Inductive Fuze Setter. The inductive set message sent to MFF provides the mode plus other information necessary to opti-mize the performance against the intended target. The one parameter that is included in every set message is the time of flight. The time of flight is used to increase over-head safety by delaying the charging of the fire circuit until around 2 seconds before reaching the target. Since the fire circuit must be charged to the PD Backup to work, even the PD Backup feature won't work if too short a time of flight is entered. The time of flight is also used to provide a delay in activating the fuze's radar. This delayed RF turn-on enhances counter-measures resistance. The other fuze message parameters are mode specific and are best covered with the respective modes.

4-6.1.3. Design Features. The fuze can be set in one of five modes:

4-6.1.3.1. HOB. The height of burst mode causes MFF to detonate at a selected height of burst above a surface (water or land). It is similar to the CVT mode of other fuzes except that it allows the height of burst to be selectable in 5-foot increments. The gun fire control computer con-verts from height in meters provided by the spot-ters to the closest 5-foot setting in MFF. MFF can be set to as high as 65 feet down to as low as 90 feet beneath the surface. Using heights below the surface is only applicable in area where the forest

forms a dense canopy and the intent is to detonate at a variable height below that canopy top. The height above land will tend to be higher than the height above water for the same setting. The time of flight is settable in one-second increments out to 200 seconds.

4-6.1.3.2. AIR. In the AIR mode, MFF can engage point targets such as airplanes, missiles and helicopters. To better localize the detonation, especially when the target has a low radar cross section (RCS), the GFCS computes the closing velocity between the target and the projectile and provides it to the fuze. The time of flight is entered in one-second increments out to 31 seconds. There is a self-destruct feature, which will detonate the projectile 2 seconds after the set time of flight (TOF). About one second before the set TOF, the radar will begin broadcasting and the firing circuit will be energized. From this point on, the projec-tile will detonate when it detects a target, impacts a target, detonates in self-destruct or detonates on low proximity to the surface. There is a clutter fea-ture, which the GFCS automatically turns on if the intercept is estimated to be above 200 feet. In gen-eral, turning the clutter filter off will allow increased sensitivity.

4-6.1.3.3. ET. The electronic time mode can set the time of flight with a resolution of 0.01 seconds with a time limit of 135 seconds. The time set into MFF is obtained from ballistic computation. ET, like all the other modes has a PD Backup but the time of flight still controls when the PD Backup will be turned on.

4-6.1.3.4. PD. The point detonation mode in MFF was designed to be super quick. There is a crush switch located about 0.05" beneath the tip of the radome. The fuze will detonate within micro-seconds of switch closure. This design approach was selected to prevent the fuze from being dam-aged by a hard target before it can detonate the warhead, but still be sensitive enough to detect soft target impacts.

4-6.1.3.5. AUT. The autonomous (AUT) mode is the default mode, in which the MFF looks for an air target for the first 10 seconds of flight and then switches to a 25-ft HOB for the remainder of the

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flight. The fuze activates in the AUT mode after being fired without a valid setting in memory. Since the minimum memory retention time is 5 minutes, a projectile fired more than 5 minutes after being set may default to the AUT mode. A projectile fired more than 24 hours after being set will default to AUT. Without the time of flight information, the fuze must be ready to engage a target throughout its entire flight and therefore the additional overhead safety and countermeasures resistance obtained by delaying the RF turn-on and firing circuit charging are not possible with the AUT mode.

4-6.1.4. Other Features - Overview.

4-6.1.4.1. Telemetry. The fuze has a telemetry feature that was intended for use only during devel-opment and fuze lot acceptance testing. The telem-etry is turned on via a bit in the fuze set message. When the telemetry is turned on, it broadcasts coded pulses using the fuze's radar during the first half-second and other times during flight. The telemetry can verify the mode the fuze is activated in, provide S&A arm time (if the fuze is so equipped with the arm sensor) as well as other per-formance information during flight. Special equip-ment is required to receive the telemetry broadcast.

4-6.1.4.2. Test Feature. The fuze is designed so that fuze electronics can be functional tested (except for the battery and PD crush switch which are one use only devices) by removing the explo-sive components, inserting a test plug and then put-ting the fuze in a test chamber. Each fuze is tested in the factory before the explosive components are added and its performance information is saved for comparison during future surveillance testing.

4-6.1.4.3. Inductive Setting. The fuze was designed to be compatible with the MK 34 Fuze Setter in the MK 45 Gun Mount. The Message for-mat required to set all of the fuze modes is illus-trated in Table 4-9. Each MFF message has a start bit and the same 5 bit round ID number. Then comes the 3 bits to select the mode. Each set mode has a time of flight and a telemetry enable bit. The telemetry feature within the fuze is intended for use during development and lot acceptance testing, and should not be used by the Fleet. During the induc-tive setting process, the message received by the

fuze is sent back to the setter during the talk-back phase at which time the correct receipt of the mes-sage is confirmed. Between the talk-forward and talk-back phases the fuze reviews the message and if it looks like a viable message it places that mes-sage in memory and talks back that message. If the message does not consider the received message viable, it puts the Autonomous message in memory and send, the Autonomous message during talk-back. The fuze has an interrogate feature which requires special equipment to exercise. During interrogation, the interrogate message is sent to the fuze and the fuze talks back the message it had in memory prior to interrogation. This interrogation feature is only used during development.

4-6.1.5. Safety through Safe Separation Overview. There are a number of redundant safety features to ensure safety from round assembly through safe separation for the ship. They are composed of firmware, electrical hardware and mechanical hardware. The single most important mechanical hardware device is the Safety and Arming (S&A) device.

4-6.1.5.1. S&A. The MFF S&A is illustrated in Figure 4-57. The function of the S&A is to block the output from the electric detonator from reaching the booster until the projectile has traveled a safe distance from the ship. The S&A is a purely mechanical clock-like mechanism that in effect counts the number of revolutions the projectile makes. Once sufficient revolutions have occurred, the S&A rotor, which was blocking the explosive transfer, swings into the armed position aligning the explosive lead in the rotor with the detonator and booster. The actual distance traveled before arming is a function of the gun rifling pitch and projectile diameter. In order to unlock the S&A rotor and begin its rotation, it must experience a sufficient setback force (monitored by the setback pin) and a spin rate of at least 75 RPS (monitored by the spin detents). Although the projectile is rotating while in the gun barrel, the mechanical counting mechanism does not begin counting until muzzle exit because the friction on the S&A rotor during in-bore acceleration is sufficient to immobilizes it. The functional parameters of the S&A are also provided in Table 4-10. To get S&A arm time data during

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development and lot acceptance testing, a small magnet is added to the S&A rotor and just forward of the S&A on the detonator block, a Hall Effect sensor was added. When the S&A arms, the Hall Effect sensor detects the magnet on the rotor when it locks in the armed position. If the telemetry feature is turned, on the fuze microprocessor monitors the status of the Hall Effect sensor and broadcasts when the arming occurs.

4-6.1.5.2. Electrical Hardware. To provide redundant safety during safe separation, an RC delay circuit was incorporated which will prevent

charging the firing capacitor to the maximum no fire level for 0.230 seconds after the battery has been activated during gun launch.

4-6.1.5.3. Firmware. The firmware within the microprocessor provides the delay to the charging circuit. Table 4-10 provided both the RF activation and firing circuit charging delays in the firmware.

4-6.1.5.4. Safety Time-line. Table 4-11 and associated Figure 4-58 illustrate all of the above safety features. In the AUT mode, the fuze must be ready to engage a target at 1400 feet; therefore, all electrical and mechanical safeties must be removed by then.

Table 4-9 Fuze Setting Message Format

FUNCTION MODESTART

BIT ROUND ID MODE SELECT DATA BITS LAST BIT

B0 B1-B5 B6-B8 B9-B24 B25

AIR TARGET PROXIMITY (AIR) 1 00100 100 XXXX XYYY YYYY

WZSP 0

SURFACE TARGET PROXIMITY (HOB) 1 00100 011 HHHH HXXX XXXX

X0SP 0

AUTONOMOUS (AUT) 1 00100 000 UU00 0000 0000 00SP 0

POINT DETONATION (PD) 1 00100 001 XXXX XXXX 0000

00SP 0

ELECTRONIC TIME (ET) 1 00100 010 TTTT TTTT TTTT TTSP 0

Where:B0 B25 : Bit location in setting messageH : Height of burst (HOB) in 5ft increments (65-HOB/5) P : Parity bit [set/clear to maintain even parity]S : Self -TM enable [enable 1, disable 0] T : Time of Flight (TOF) to target (10 milliseconds/increment) W: Self destruction enable [enable 1, disable 0] X : Time of Flight to target (1 second/increment)Y : Relative closing velocity (CV) in feet per second at detonation [integer((CV-822)/42)] Z : Clutter rejection enable [enable 1, disable 0] Specialized settings used only during verification testsUU: 2 bit transition time code used only when Self -TM enabled

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Spin < 50 RPS no armSpin > 75 RPS all arm

Set back force on pin < 0.833 lbf no arm (approx 1,000 Gs)Set back force on pin > 2.224 lbf all arm (approx 3,000 Gs)

Average Arming Distance for LRIP Fuzes = 1141 feet

Figure 4-57 S&A Locking Features

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Table 4-10 Overhead Electrical Safety Features

FUNCTION MODE

TIME TO REACH MNFS LEVEL ON THE FIRING CIRCUIT RF TURN ON TIME

AIRShall not occur prior to 0.180 sec after gun fire and not prior to (TOF (2+0.125xTOF)) 0.220 sec

Shall not be programmable to occur prior to 0.144 sec from gun firing and not prior to (TOF 1)-0.220 sec

HOBShall not occur prior to 0.180 sec after gun fire and not prior to (TOF (2+0.125xTOF)) 0.285 sec

Shall not be programmable to occur prior to 0.144 sec from gun firing and not prior to (TOF (2.22+0.03125xTOF))-0.285 sec

AUTO Shall not occur prior to 0.180 sec after gun fire (no extra overhead safety)

Shall not occur prior to 0.144 sec from gun firing

PDShall not occur prior to 0.180 sec after gun fire and not prior to (TOF (2+0.125xTOF)) 0.285 sec

Not applicable

ETShall not occur prior to 0.180 sec after gun fire and not prior to (TOF (0.100 + time to minimum all fire energy)) 0.220 sec

Not applicable

Table 4-11 Safety Time Line for 5”/54 Service Charge Firing

DISTANCE FROM BREECH ATTIME FROM BREECH

EXPLANATION OF COMPLETING SAFETY FEATURES' FUNCTIONS IN PREPARATION FOR DETONATION

Before firing All safety features engaged

0.1ft at0.001 sec

The setback pin unlocks the S&A rotor.The spin detents unlocks the S&A rotor.Battery activation begins.

22.5 ft (muzzle exit) at 0.015 sec Battery fully activatedRotor begins to rotate

513 ft at0.200 sec

Independent RC hold-off circuit allows firing capacitor to begin charging (first of 2 required events). See Figure 4-58.

592 ft at0.230 sec

Earliest charging of the firing capacitor as controlled by microprocessor firmware (second of two required events). This event is delayed until the projectile is near the target if the fuze is set (provides over-head safety). See Figure 4-58.

664 ft at0.257 sec

Time to reach maximum no-fire voltage on firing capacitor. See Figure 4-58.

847 ft at0.326 sec

Time to reach the minimum all-fire voltage on the firing capacitor controlled by the resistor

865 ft at0.333 sec

Earliest RF turn-on. This event is delayed until near the tar-get if the fuze is set (over-head safety).

1144 ft at0.424 sec (approx)*

Earliest S&A arm distance (-3 sigma distance location)

1122 ft at0.430 sec

RF earliest ready-to-engage-target time.

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4-6.1.6. Functional Description.

4-6.1.6.1. HOB. To provide an HOB that is independent of surface reflectivity, the fuze moni-tors the 2nd and 4th harmonic of the Doppler return from the surface and compares their amplitudes. The output voltage for the 4th harmonic is nor-mally larger than the 2nd harmonic. The Bessel-function nature of the Doppler radar return causes the 4th harmonic to peak before the 2nd har-monic. During engagement, as the fuze descend past the peaking for the 4th harmonic, the 4th har-monic amplitude falls and the 2nd harmonic ampli-tude rises. The gain on these two harmonics is set so that at 65 feet above the surface the amplitude of the 2nd harmonic exceeds the 4th harmonic. If the fuzes is set for 65 feet, the fuzes detonates immedi-ately when the 2nd harmonic exceeds the 4th har-monic. If the fuze was set for a lower height, it measures the rate of descent using the Doppler fre-quency and calculates the time to reach selected height. Below 65 feet, the fuze detonates at the time calculated to reach the set height.

This signal processing approach of using a comparison between the 2nd and 4th harmonics compensates for the variation in surface reflectiv-ity, but it does not compensate for multipoint returns from the surface. As a result, if the projec-tile is descending over a smooth water surface, the only Doppler return will be from perpendicular to the surface and the measured height will be exactly 65 feet. On the other hand, if the surface is rough water or land, there will be a number of points pro-

viding Doppler return. The fuze will use the aver-age of these measured distances as its height and, therefore, assumes it is higher than it actually is. As a result, the fuze had an average bias of about 10 feet (low) during development. To correct for this bias, the production fuzes automatically adds 10 feet to the selected HOB before it begins signal processing. With this change, the 65 ft and 60 ft settings must now be processed as if it was set to 55 feet. For the Fleet fuzes when the height setting is 55 feet or below, the average HOB is bias free over the spectrum of surfaces. During an engage-ment, the characteristics of a particular impact sur-face will be constant and therefore if an HOB up/down spot is made it should correct for the local surface characteristics and provide an improved HOB pattern.

4-6.1.6.2. AIR. The MFF RF design is far more sensitive than previous VT-RF fuzes. When engaging air targets, the fuze tracks the target and measures its relative velocity. As the projectile gets closer to the target, its relative velocity decays as a function of the Cosine of the angle with the target. See Figure 4-59. The fuze contains a look-up table, which uses the input closing velocity to look up the closing velocity that produces the optimum fuzing angle. When the measured velocity decays to this optimum value, the fuze detonates the projectile. This is relatively straightforward at altitudes where the only RF return is from the target being engaged.

1436 ft at0.555 sec (approx)*

Latest S&A arm distance (+3 sigma distance)

Beyond 1290 ft (nominal) feet Overhead safety is controlled by delaying firing capacitor charging by microprocessor until near the target. (Since, in the Autonomous mode, the fuze does not know when it will encounter a target, delayed charging of the firing capacitor is not possible.)

* Velocity-dependent characteristic

Table 4-11 Safety Time Line for 5”/54 Service Charge Firing (Continued)

DISTANCE FROM BREECH ATTIME FROM BREECH

EXPLANATION OF COMPLETING SAFETY FEATURES' FUNCTIONS IN PREPARATION FOR DETONATION

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Figure 4-58 Electrical Safety Pertaining to Firing Circuit Operation

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When engaging air targets near the surface, the RF return must be processed to filter out surface clutter before the target can be successfully engaged. The fuze uses a switched capacitor filter (SCF) to actively control the filtering levels. The sea clutter filter approach used is based upon the assumption that sea clutter looks like stationary tar-gets. Since the projectile velocity is known, as a function of time, the SCF can be automatically changed to filter out the slow relative velocity of this stationary clutter. If all of the air targets had a high velocity, the signal processing could be just that simple; however, it is not that simple. To allow slow air targets near the surface to be detected and then tracked down to the correct fuz-ing angle (velocity provided in the look-up table), a two-stage filter was required. The first stage of the filter steps the clutter filter down as a function of time of flight so that the filter level will be at 90% of the closing velocity on a stationary target. The second stage of the filter begins after the fuze has detected and are locked onto a target. During this second stage, the filtering is dropped to lowest level. With this low setting, the fuze will be able to track the detected target down to the optimum fuz-ing angle. The sea clutter is automatically turned on when the target intercept is expected to be below 200 feet. The high pass filter constraint of 90% of projectile velocity allows a +/- 26-degree look angle for stationary targets. The look angle constraint opens significantly as the incoming velocity of the target increases. At altitudes above 200 feet, the filter uses the minimum filter level (same as the second stage). At this minimum filter level, the fuze should function better against low RCS and slow targets.

The height above the ocean down to which the first stage filter can effectively filter out sea clutter is a function of sea state and angle of fall when the projectile reached the surface. Limited testing to date indicates that the filter may allow the fuze to engage stationary helicopters or surface craft down to 30 feet (or lower) above the surface during sea state 3 or possibly higher.

If the self-destruct feature is not selected, the fuze will continue to search for a target until it eventually falls to the surface, at which time it will detonate in proximity to the surface. If the fuze is

set to a TOF of 31 seconds, it automatically turns off the self-destruct feature so that targets beyond 31 seconds can be engaged.

4-6.1.6.3. ET. The ET mode detonates the pro-jectile a precise time after being fired. The opera-tor never deals directly with time. The GFCS software computes the time of flight based upon the range to the selected target. If the height of burst required is in excess of 65 feet, the ET mode will be employed. Against an air target, the ET mode will automatically be employed if the inter-cept velocity is expected to be outside the perfor-mance limits of the AIR mode. It also makes sense to employ the ET mode when the RCS of the target is expected to be below what the fuze can detect.

The fuze uses a crystal oscillator to measure time. In operation, the battery activates when it experiences the gun launch environment, the elec-trical power causes the microprocessor to reset and power-up and then the time measurement begins. To compensate for the battery activation and microprocessor start-up times, the time counter actually begins at the value of the delay that was identified during initial testing. The FAAT and LAT data was taken for a time of flight of approxi-mately 34 seconds (17K yds). The results from these tests were a standard deviation of 0.006 sec-onds and a bias of 0.006 seconds short. This accu-racy easily meets the requirements. The bias can be corrected by the GFCS during setting.

4-6.1.6.4. Autonomous (AUT). After the first 10 seconds of flight, the AUT mode is identical to the HOB mode set to 25 feet (except the RF is on continuously). The first 10 seconds of flight are similar to the AIR mode; however, since the fuze does not have the closing velocity information input, it must work a little differently. During the air portion of the AUT mode, the radar continu-ously searches for a target. Once it detects a target, the initial closing velocity is measured from the detected target as if it had been input during the setting process. At that point, it is basically the same as the AIR mode engaging a target low over the water with self destruct turned off.

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4-6.1.6.5. Additional Details on Modes of Operation.

4-6.1.6.5.1. HOB. To provide an HOB that is independent of surface reflectivity, the fuze moni-tors the 2nd and 4th harmonic of the Doppler return from the surface and compares their amplitudes. The output voltage for the 4th harmonic is nor-mally larger than the 2nd harmonic. The Bessel function nature of the Doppler return causes the 4th harmonic to peak before the 2nd harmonic. During engagement as the fuze descend past the peaking for the 4th harmonic, the 4th harmonic amplitude

falls and the 2nd harmonic amplitude rises. The gain on these two harmonics is set so that at 65 feet above the surface the amplitude of the 2nd har-monic exceeds the 4th harmonic. If the fuze is set for 65 feet the fuze detonates immediately when the 2nd harmonic exceeds the 4th harmonic. If the fuze was set for a lower height, it measures the rate of descent using the Doppler frequency and calcu-lates the time to reach selected height. Below 65 feet, the fuze detonates at the time calculated to reach the set height.

Figure 4-59 AIR Mode Geometry

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This signal processing approach compensates for the variation in surface reflectivity but it does not compensate for multipoint returns from the sur-face. As a result, if the projectile is descending over a smooth water surface, the only Doppler return will be from perpendicular to the surface and the measured height will be exactly 65 feet. On the other hand, if the surface is rough water or land there will be a number points providing Doppler return. The fuze will use the average of these mea-sured distances as its height and, therefore, assumes it is higher than it actually is. This resulted in the fuze having an average bias of about 10 feet (low) during development. To correct for this bias, the production fuze automatically add 10 feet to the selected HOB before it begins signal processing. With this change, the 65 ft and 60 ft settings must now be processed as if it were set to 55 feet. For the Fleet fuzes, when the height set-tings is 55 feet or below, the average HOB is bias free over all surfaces. During an engagement, the characteristics of a particular impact surface will be constant and, therefore, if an HOB up/down spot is made it should correct for the local surface char-acteristics and provide an improved HOB pattern.

4-6.1.6.5.2. AIR. The MFF RF design is far more sensitive than previous VT-RF fuzes. When engaging air targets, the fuze tracks the target and measures its relative velocity. As the projectile gets closer to the target, its relative velocity decays as a function of the Cosine of the angle with the target. See Table 4-10. The fuze contains a look-up table that has the closing velocity at the opti-mum fuzing angle based upon the input closing velocity. When the measured velocity decays to this optimum value, the fuze detonates the projec-tile. This is relatively straight forward at altitudes where the only RF return is from the target being engaged.

When engaging air targets near the surface, the RF return must be processed to filter out surface clutter before the target can be successfully engaged. The fuze uses a switched capacitor filter (SCF) to actively control the filtering levels. The sea clutter filter approach used is based upon the assumption that sea clutter looks like stationary tar-gets. Since the projectile velocity is known as a function of time, the SCF can be automatically

changed to filter out the slow relative velocity of this stationary clutter. If all of the air targets had a high velocity, the signal processing could be just that simple; however, it is not that simple. To allow slow air targets near the surface to be detected and then tracked down to the correct fuz-ing angle (velocity provided in the look-up table), a two stage filter was required. The first stage of the filter steps the clutter filter down as a function of time of flight so that the filter level will be at 90% of the closing velocity on a stationary target. The second stage of the filter begins after the fuze has detected and is locked onto a target. During this second stage, the filtering is dropped to lowest level. With this low setting, the fuze will be able to track the detected target down to the optimum fuz-ing angle. The sea clutter is automatically turned on when the target intercept is expected to be below 200 feet. The high pass filter constraint of 90% of projectile velocity allows a +/- 26 degree look angle for stationary targets, but this look angle constraint opens significantly as the incoming velocity of the target increases. At altitudes above 200 feet, the filter uses the minimum filter level (same as the second stage). At this minimum filter level, the fuze should function better against low RCS and slow targets.

The height above the ocean down to which the first stage filter can effectively filter out sea clutter is a function of sea state and angle-of-fall when the projectile reached the surface. Limited testing, to date, indicates that the filter may allow the fuze to engage stationary helicopters or surface craft down to 30 feet above the surface or lower during sea state 3 or possibly higher.

If the self destruct feature is not selected, the fuze will continue to search for a target until it eventually falls to the surface, at which time it will detonate in proximity to the surface. If the fuze is set to a TOF of 31 seconds, it automatically turns off the self destruct feature so that targets beyond 31 seconds can be engaged.

4-6.1.6.5.3. ET. The ET mode detonates the pro-jectile a precise time after being fired. The time is automatically entered by the GCFS based upon the target and scenario of the engagement.

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The fuze uses a crystal oscillator to measure time. In operation, the battery activates when it experiences the gun launch environment, the elec-trical power causes the microprocessor to reset and power-up and then the time measurement begins. To compensate for the battery activation and microprocessor start-up times, the time counter actually begins at the value of the delay that was identified during initial testing. The FAAT and LAT data were recorded for a time of flight (TOF) of approximately 34 seconds (17K yds). The results from these tests were a standard deviation of 0.006 seconds, and a bias of 0.006 seconds short. This accuracy easily meets the requirements. The bias can be corrected by the GFCS during set-ting.

4-6.1.6.5.4. Autonomous (AUT). After the first 10 seconds of flight, the AUT mode is identical to the HOB mode set to 25 feet (except the RF is on continuously). The first 10 seconds of flight are similar to the AIR mode; however, since the fuze does not have the closing velocity information input, it must work a little differently. During the air portion of the AUT mode, the radar continu-ously searches for a target. Once it detects a target, it uses the initial closing velocity it measures from the detected target as if it had been input during the setting process. At that point it is basically the same as the AIR mode engaging a target low over the water with self destruct turned off.

4-6.1.6.6. Use. 5-inch, HE projectiles

4-6.1.6.7. Physical Characteristics.Specification

Drawing .............................. 53711-7100370Weight .......................................2.05 poundsLength ........................................ 5.97 inchesThread size.........................2.000-12UNS-lADiameter, max............................. 2.42 inchesIntrusion ..................................... 2.21 inches

4-6.1.6.8. Explosive Components.Electric detonator ....................................DXN1Lead..................................................... PBXN-5Booster ................................................ PBXN-5

4-6.1.6.9. Arming.First safetySetback

No arm ......................................... 2,000 g'sArm.............................................. 3,000 g's

Second safetySpin

No arm .............. 70 revolutions per secondArm ................ 120 revolutions per second

Other safetyElectronic firing enables 7 seconds,maximum, prior to proximity setting.

Arming delayProjectile revolutions from muzzle 25, min

4-6.1.6.10. Operational Characteristics.Modes

Proximity ............... 5- to 150-second setting;2 PD backups, mechanical

(sliding stab detonator) andelectric (impact switch)

PD ........ mechanical (sliding stab detonator)Proximity timing

Turn-on time = 0.98 multiplied by (set time .minus 5 seconds) + 2 seconds

Proximity firing enable time = Turn-on time plus 2 seconds +0.3 second

Burst height (proximity)

4-6.2. 3P Fuze.

4-6.2.1. The 3P fuze is designed to be pro-grammed for the following six function modes:

a. Time gated proximity (TGP)

b. Time gated proximity with impact priority (TGPIP)

c. Point-detonating (PD)

d. Armor-piercing PD delay

e. Electronic time

f. Proximity with self-destruct

4-6.2.2. The 3P fuze consists of the two major parts shown in Figure 4-60 . The left image illus-trates the mechanical part with the safety arming

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devices and the pyrotechnics. The right image illustrates the electronic part for data storage, sig-nal processing, control of fuze functions, time set-ting, etc. The electronics also include circuits for electronic counter-countermeasures (ECCM) and automatic sensitivity regulation plus battery and impact triggering devices.

4-6.2.3. The fuze of each cartridge is individu-ally programmed from a proximity fuze program-mer (PFP) a few milliseconds before firing. The PFP receives a constant flow of data from the fire control computer about selected mode, predicted time of flight, etc. In the PFP, the data are trans-formed to Doppler channel and high frequency (HF) messages that are transmitted to the fuze. A 3P cartridge loses its memory if not fired after a short while and can then be reprogrammed.

4-6.2.4. The fuze relies on three independent safety and arming (S&A) environments:

• Rotation

• Acceleration

• Time (electric clock controls an electric igniter).

4-6.2.5. The acceleration and rotation safety devices release just after firing and an electric clock begins the timed arming sequence in accor-dance with Bofors documentation. The clocking sequence to arming time sets an electric igniter that initiates movement of the arming pin and release of the shutter. Bofors has stated this fuze design com-plies with MIL-STD-1316. The minimum arming distance is approximately 200 m. The arming safety acceleration and rotation thresholds are pre-sented in Table 4-12 . The fuze function accelera-tion and rotation thresholds are presented in Table 4-13.

Figure 4-60 3P Fuze Components

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Table 4-12 3P Fuze No-Arm and All-Arm Ballistic Thresholds

No Arming All Arming

First Safety 12,000 accelerations of gravity (g) 20,000 g

Second Safety 250 revolutions per second (rps) 500 rps

Table 4-13 3P Fuze Ballistic Function Threshold

Nominal Values

Rotation 767 revolutions per second (rps)

Acceleration 35,000 accelerations of gravity (g)

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4-7. AUXILIARY DETONATING FUZES

4-7.1. General. An auxiliary detonating (AD) fuze is used in conjunction with a nose fuze to pro-vide additional safety. An AD fuze has an arming system that operates independently from the nose fuze. If the nose fuze is accidentally initiated before the AD fuze is armed, the burster charge in the projectile is not exploded. The explosive train is maintained out of alignment from at least when the projectile clears the muzzle of the gun on firing to a few hundred feet, depending on the AD fuze. It is initiated by the nose fuze and produces an out-put required to function the projectile. In the case of HE projectiles, the booster in the AD fuze cre-ates an explosion of sufficient magnitude to initiate the projectile. For WP and illuminating projectiles, the AD fuze has either a black powder magazine output or only a lead.

4-7.1.1. Location. AD fuzes are located in line behind the nose fuze. When used with PD fuzes or MT fuzes, the AD fuze is placed in contact with the burster charge when the projectile is loaded. In the case of older VT and CVT fuzes, AD fuzes were contained inside and considered part of the nose fuze.

4-7.1.2. Safety Features. There are two gener-ations of AD fuzes. In older AD fuzes, MK 89 and lower, the explosive train is maintained out of alignment and the firing pin is blocked by spring-loaded centrifugal detents. After the detents are removed, lead counterweights in the rotor cause it to turn to the armed position under continued cen-trifugal force. Newer fuzes, MK 384 and higher, use the MK 41 DASD. In addition to spin detents, the rotor in the MK 41 is initially locked with a set-back pin. After the setback pin and spin detents are removed, the rotor turns and locks in the armed position by an escapement gear train. Output from the nose fuze drives the firing pin into the rotor det-onator initiating the AD fuze explosive train.

4-7.2. Fuze MK 54 (Auxiliary Detonating).

4-7.2.1. General. The MK 54 AD fuze (Figure 4-61) is spin armed. The firing pin is held forward by spin detents and the detonator assembly is out of line until armed by a rotational velocity between 50 and 75 revolutions per second. There are three. MOD 1 is similar to MOD 0 except that it has an aluminum body. MOD 2 is similar to MOD 0 except for its booster lead-in; MOD 2 has two increments of tetryl in its lead-in, while MOD 0 has a small single tetryl pellet.

Figure 4-61 Fuzes MK 54 MOD 2, MK 55 MOD 0 and MK 89 MOD 0 (Auxiliary Detonating), Cutaway View and Exploded View of Arming Mechanism

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4-7.2.2. Use.5-inch, 54 caliber projectiles


Specification ...................................WS 14161 Drawing ...............................................490100

Weight............................................0.76 pound Length............................................2.50 inches Thread size...........................1.375-20NS-2LH

4-7.2.4. Explosive Components.Rotor detonator

MK 54 0 and 1 ........................MK 28 MOD 0 MK 54 MOD 2 ....................... MK 28 MOD 1

NOL 130 mix, lead azide and tetrylBooster lead-ins ..................................... TetrylBoosters ................................................. Tetryl

4-7.2.5. Arming.No arm........................50 revolutions per secondArm.............................75 revolutions per secondArming distance (from muzzle) ..........5 to 6 feet

4-7.2.6. Function.Type.................................................. MechanicalDelay .............................................Instantaneous

4-7.2.7. Packing.MOD 0/1 ................... 150/box; 152 pounds;

1.25 cubic feet MOD 2......................................................36/box

4-7.3. Fuzes MK 395, MK 396 and MK 411 (Auxiliary Detonating).

4-7.3.1. General. There are two modern AD fuzes used in Navy gun ammunition. Arming and functioning of the two are identical; they differ only in their adapter assembly and output. The two models are used in 5-inch, 54 caliber ammunition. The MK 395 is used on HE rounds with PD or MT nose fuzes and has nominal 200-gram boosters to effectively explode the main charge. MOD 0 and MOD 1 fuzes use tetryl and CH-6, respectively, as the booster explosive. The MK 396 is used with a PD or MT nose fuze on smoke or illuminating rounds and have neither a booster nor an expelling charge. Table 4-14 summarizes the applications for each AD fuze and gives the overall physical characteristics. Figure 4-62 through Figure 4-65show the MK 41 DASD and each of the AD fuzes. These fuzes are used in conjunction with a suitable MT or PD fuze to provide safe separation of the projectile from the gun. The AD fuzes have inde-pendent gun environmental safety locks (spin and setback) on the out-of-line explosive train inter-rupter, a spin-activated delay arming mechanism to provide safe separation of the projectile from the gun, and a mal-assembly feature to prevent a pre-armed interrupter from being assembled into the fuze.

Table 4-14 Characteristics of Modern Auxiliary Detonating Fuzes

MK 395 MODS 0 & 1 MK 396 MOD 0 MK 411 MOD 0

Figure Figure 4-63 Figure 4-64 Figure 4-65

Gun 5-inch, 54 caliber

Ammunition HE-PD, HC-PD,AAC-MT

Smoke-PD,Illum-MT,

Smoke-MT

Illum-MT

Type Mechanical

Specification WS 13598 WS 18488

Drawing 2512190 2506736 5177470

Weight 1.5 lbs. 0.77 lbs. 0.97 lbs.

Length 5.74 in. 2.5 in. 3.5 in.

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4-7.3.2. Description. The fuzes incorporate a spin activated delay arming mechanism. The delay arming mechanism (Figure 4-62) consists essen-tially of a rotor with an out-of-line detonator and a gear train. The delay arming mechanism is housed in a cavity in the center of the fuze body and is retained in this cavity by a firing pin and (threaded) support assembly. The firing pin is fixed in the center of this assembly so that when the (rotor) det-onator is in the armed position it is aligned with the firing pin. The cavity, which houses the delay arm-ing mechanism, is threaded to accommodate the firing pin and support assembly and the threads of the nose fuze body.

4-7.3.3. Operation. In the unarmed position, the rotor is locked out of line by two spin detents and a setback pin. When the projectile is fired, gun

setback forces remove the setback pin from block-ing the rotor, and centrifugal force moves the rotor detents outward to enable the rotor to turn freely. The turning speed of the rotor is controlled by the gear train. A spring-loaded pin in the rotor rides under a movement plate. When the rotor reaches the armed position, this pin engages a hole in the movement plate and locks the rotor in the armed position. A spin of 50 to 75 revolutions per second is required to arm these fuzes. Upon detonation of the nose fuze, the firing pin is driven into the deto-nator and fires the detonator which, in turn, initi-ates the booster (via a tetryl lead), which explodes the main charge of the projectile.

Cross Section 2.75 in.

Intrusion depth

5.1 in. 1.5 in. 2.48 in.

Intrusion diameter

2.0 in. 1.88 in. 2.0 in.

Thread 2.35 -10NS-2

Thread depth 0.71 in.

Detonator MK 23, NOL 130, lead azide, tetryl (in MK 41 DASD)

Lead 550 mg tetryl

Booster or expelling charge

MOD 0: 200 g. tetrylMOD 1: 208 g. CH-6

None 23 g. Black powder

Setback 900 g no arm; 1385 g all arm

Spin 50 rps, no arm; 75 rps, all arm

Safe separa-tion

360 ft. min., 37 to 52 turns to arm

Packing 42/box,105 lbs.,3.5 cu. ft.

84/box100 lbs.,3.5 cu. ft.

60/box,55 lbs,

2.18 cu. ft.

Table 4-14 Characteristics of Modern Auxiliary Detonating Fuzes (Continued)

MK 395 MODS 0 & 1 MK 396 MOD 0 MK 411 MOD 0

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Figure 4-62 Delay Arming Safety Device MK 41 MODs 0 and 1, Assembled View and View with Top Plate Removed

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Figure 4-63 Typical Applications of Fuze MK 395 MOD 0 (Auxiliary Detonating), Cross-Sectional View

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Figure 4-64 Fuze MK 396 MOD 0 (Auxiliary Detonating), Cross Sectional View

Figure 4-65 Fuze MK 411 (Auxiliary Detonating), Cross-Sectional View

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CHAPTER 5

PRIMERS

5-1. INTRODUCTION For gun ammunition the term “primer” usually

means the small tube of sensitive explosive that initiates the burning of the propellant charge. This chapter describes Navy gun-type ammunition primers for 20mm through 5-inch, 54 caliber gun ammunition in current use. The information pre-sented is arranged by primer classification and then by mark and MOD numbers. A synopsis of primers with assignment to gun or use is given in Table 5-1.

5-2. CLASSIFICATION OF PRIMERS

5-2.1. Method of Firing. Primers can be classi-fied according to the methods used in firing them as follows:

5-2.1.1. Electric. Electric primers are fired by passing a current through a built-in resistance fila-ment that is surrounded by an initiating explosive mixture, or they are fired by passing a current through an initiating explosive mixture that is elec-trically conductive.

Table 5-1 Primers by Mark and MOD with Assignment to Gun or Use

Type of Caliber of Ammunition Used In

PRIMER 20MM 40MM 57MM 76MM, 62-CAL 5-IN, 54-CAL

MK 15 MOD 2 ET1

MK 22 MOD 2 P

MK 45 MOD 1 E2

MK 48 MOD 2 E3

MK 153 MOD 1 E4

MK 161 MOD 0 P

M52A3B1 PCE

M2000 E

PRIMER LEGEND

P = Percussion

PCE = Percussion Cap, Electric

ET = Electric Test

E = Electric

1 - Has percussion element but can only be fired electrically in 5 inch 54 caliber gun

2 - Full charge only

3 - Clearing charge only

4 - Reduced charge only

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5-2.1.2. Percussion. Percussion primers are fired by the mechanical impact of the firing pin.

5-2.1.3. Combination. Combination primers can be fired by either electricity or percussion. Electrical firing is considered the primary method; the percussion feature is a standby for use when the electrical firing fails

5-2.2. Usage. Primers can be further classified by their usage, as follows:

5-2.2.1. Case. Case primers are used in fixed and separated ammunition wherein they are nor-mally an integral part of the cartridge case as received aboard ship. Such primers are threaded or press-fitted into the base of the cartridge case. The case primer contains a sufficient charge of black powder or other ignition mixture to ignite the pro-pellant in the case.

5-2.2.2. Test. Test primers are for use in testing the electric firing circuit. The MK 15 combination primer is used to test the integrity of the 5-inch fir-ing circuit. The primer is placed in a special short-ened case and produces an audible indication circuit is good and can fire a round. However, the MK 15 primer is being replaced with the MK 55 Electronic Firing Circuit Tester (see paragraph 5-5.1.).

5-3. ELECTRIC PRIMERS Some electric primers are initiated when the

firing pin contacts a button that is in contact with a conductive explosive mixture such as the electric cap. Other electric primers are initiated through a resistance wire that is surrounded by finely granu-lated black powder or embedded in an explosive mixture. The fine-grain black powder ignites the coarser black powder to build up enough heat and pressure to initiate the smokeless powder propel-lant charge.

5-3.1. Case Electric Primer. This type of primer is secured to a cartridge case by the threads on its stock. Case electric primers are used in pro-pelling charges for the newer rapid-fire (RF) case guns.

5-3.1.1. Description. This class of primer (Fig-ure 5-1) consists of a bridgewire surrounded by an explosive mixture, small black powder booster charge, and a main black powder charge. The ignition element consists of two resistance fila-ments connected in parallel. They are insulated from the case so that the firing current must pass through the ignition element. Figure 5-1 provides a cutaway diagram for a typical case electric primer.

5-3.1.2. Operation. When an electric current heats the bridgewire, the explosive mixture flashes and ignites the fine-grain black powder booster charge. This in turn ignites the main black powder charge of the primer. Flame from the main charge ignites the propellant.

5-3.2. Primer MK 45 MODs (Electric).

5-3.2.1. General. Primers in this series were developed to provide a nonpercussion electric screw primer for use in 5-inch, 54 caliber ammuni-tion. The MOD 0 is inactive and restricted for use because it is unsafe to use and may cause prema-ture ignition. Black powder may fall out of the ignition element and get pinched during ramming. It has been replaced by the MOD 1 (Figure 5-2), which is similar to the MOD 0 except that it uses MK 1 MOD 1 Ignition Element.

5-3.2.2. Description. The MOD 1 consists of a steel stock plug with a seamless steel primer tube containing 52 grams of class 2 black powder main charge. It uses MK 1 MOD 1 Ignition Element, which has an initiator consisting of a double-arm 0.002-inch-diameter platinum-iridium bridgewire embedded in a lead styphnate charge and a black powder booster. The ignition element used in the MOD 1 differs from that used in the MOD 0 in that a layer of Scotchcast #8 sealant is placed in the ignition cup to prevent pinching of the lead styphnate upon ramming.

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Figure 5-1 Typical Case Electric Primer, Cutaway View

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5-3.2.3. Interface.5-inch, 54 caliber

5-3.2.4. Physical Characteristics.Design data

Overall length MOD 0 ...................................21.39 inches

MOD 1 ...................................21.35 inchesBoss diameter.............................1.187 inchesWeight ......................................1.535 poundsThread dimensions

MOD 0 ....................... 1.00-20NS-2 inches MOD 1 ........................ 1.000-20UNEF-2A

Primer tube Length ....................................20.25 inches Unvented length .......................8.25 inches

Vent diameter............................. 0.218 inch No. of vents............................................ 32Components

Stock ...................................................... Steel Plug ...................................................... Brass Primer tube............................................. Steel Ignition element MOD 0................................. MK 1 MOD 0

MOD 1................................. MK 1 MOD 1

5-3.2.5. Explosive Data.Ignition charge

Lead styphnate ......................79.3 milligrams Nitrocellulose..........................1.7 milligramsBooster, class 4 black powder ...230 milligrams

Primer tube, class 2 black powder ......52 grams

5-3.2.6. Functioning Data.Primer resistance........................ 0.10-0.18 ohmRecommended current

Testing ................................... < 50 milliamps Firing .............................................> 10 amps Firing voltage ..........................20 Vac or Vdc Electrostatic sensitivity ...............8 x 105 ergs

at 400 micromicrofaradsBruceton data (typical) 50% line......5.3 amps99.9% fire level (95% confidence) 12.3 amps0.1% fire level (95% confidence).... 2.3 amps

Packing Data.Drawing 5166053 ........................ 200 per drum


5-3.3.1. General. Primers in this series were developed to provide nonpercussion electric screw primer for use in the 5-inch, 38 caliber gun. MODs 0 and 1 are inactive and restricted for use in slow-rammed guns. The MOD 0 was too long for some high density propellant powders, and it was replaced by the MOD 1. The MOD 2 has replaced the MOD 1 because of premature firings of rounds containing the MOD 1 primer.

5-3.3.2. Description. The MOD 2 (Figure 5-3) consists of a threaded stock, a brass plug, and a seamless steel primer tube containing 38.9 grams of black powder (class 2) main charge. It differs from the MOD 1 in that the MOD 2 contains the MK 1 MOD 1 Ignition Element. The MOD 1 dif-fers from the MOD 0 in that the primer tube was shortened to save steel tubing. The stock material

Figure 5-2 Primer MK 45 MOD 1 (Electric), Cross-Sectional View

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is steel instead of brass. MODs 0 and 1 use MK 1 MOD 0 Ignition Element, which has an initiator consisting of a double-arm 0.002-inch-diameter platinum-iridium bridgewire embedded in a lead styphnate charge and a black powder booster. The MK 1 MOD 1 Ignition Element differs from the MK 1 MOD 0 Ignition Element in that a layer of Scotchcast #8 sealant is used to prevent pinching of the lead styphnate upon ramming.

5-3.3.3. Interface.5-inch, 54 caliber (clearing charge)


Overall lengthMOD 0................................. 21.390 inchesMOD 1................................. 11,752 inchesMOD 2................................. 11.725 inches

Boss diameter ............................ 1.187 inches Weight ...................................1.250 pounds

Thread dimensions MOD 0................................... 1.00-20NS-2 MOD 1................................... 1.00-20NS-2 MOD 2......................... 1.000-20UNEF-2APrimer tube

Length MOD 0 ................................. 20.250 inches

MOD 1 ................................. 10.625 inches MOD 2 ................................. 10.625 inches

Unvented length......................... 3.750 inches Vent diameter................................ 0.218 inch

No. of vents MOD 0....................................................44 MOD 1....................................................18 MOD 2....................................................18Components

Stock.......................................................Steel Plug .......................................................Brass Primer tube.............................................Steel Ignition element MOD 0 .................................MK 1 MOD 0 MOD 1 .................................MK 1 MOD 0 MOD 2 .................................MK 1 MOD 1


Lead styphnate ..................... 79.3 milligramsNitrocellulose ......................... 1.7 milligrams

Booster, class 4 black powder... 230 milligramsPrimer tube, class 2 black powder ...38.9 grams

5-3.3.6. Functioning Data.Primer resistance......................0.10 – 0.18 ohmRecommended current

Testing ................................... < 50 milliamps Firing.............................................> 10 amps Firing voltage ..........................20 Vac or Vdc Electrostatic sensitivity ...............8 x 105 ergs

at 400 micromicrofarads

5-3.3.7. Packing Data.Drawing 5166059 ...........200 primers per drum

Figure 5-3 Primer MK 48 MOD 2 (Electric), Cross-Sectional View

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5-3.4. Primer M52A3B1 (Electric).

5-3.4.1. General. Primer M52A3B1 (Figure 5-4) was developed by the Army to provide a nonper-cussion electric conductive primer mix for use in 20mm ammunition and is used by the Navy in the MK 11 and MK 12 guns.

5-3.4.2. Description. The primer ignition charge consists of lead styphnate, barium nitrate, calcium silicide, acetylene black, and gum arabic.

5-3.4.3. Interface.20mm AC


Overall length ............................... 0.256 inch

Cup diameter ...............................0.3325 inch Weight ..........................................1.43 grams Thread dimensions ............................Push-fitComponents

Cup ........................................................Brass Button.................................................Copper


Conductive mix ..........See Drawing 7548063

5-3.4.6. Functioning Data.Primer resistance1,000 ohms to 1.2 megohms

5-3.4.7. Packing Data. Standard commercial containers are used to ensure transportation accord-ing to 49 CFR 100-199.


5-3.5.1. General. The MK 153 MODs 0 and 1 primers are electric screw type primers developed especially for use in the 5-inch, 54 caliber reduced charge round. Primer MK 40 MOD 2 was modi-fied by shortening the primer tube to 6.65 inches and thereby forming the MK 153 MOD 0 Primer. The MOD 1 differs from the MOD 0 in that it uses MK 1 MOD 1 Ignition Element instead of MK 1 MOD 0 Ignition Element. The MOD 0 was never commercially produced.

5-3.5.2. Description. A cross-sectional view of the MK 153 MOD 1 primer is shown in Figure 5-5.

5-3.5.3. Interface.5-inch, 54 caliber

Figure 5-4 Primer M52A3B1 (Case Electric), Cross-Sectional View

Figure 5-5 Primer MK 153 MOD 1 (Case Electric), Cross-Sectional View

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Overall length .............................. 7.79 inches Boss diameter ............................ 1.187 inches Weight ......................................... 0.75 pound Thread dimensions MOD 0 .................................. 1.00-20NS-2 MOD 1 ........................ 1.000-20UNEF-2A

Primer tube Length ...................................... 6.65 inches Unvented length....................... 1.50 inches Vent diameter ............................ 0.218 inch No. of vents............................................ 14


Lead styphnate......................79.3 milligrams Nitrocellulose..........................1.7 milligramsBooster, class 4 black powder ...230 milligramsPrimer tube, class 2 black powder... 24.0 gramsComponents

Stock ...................................................... Steel Plug....................................................... Brass Primer tube ............................................ Steel Ignition element MOD 0 ................................ MK 1 MOD 0 MOD 1 ................................ MK 1 MOD 1

5-3.5.6. Functioning Data.Primer resistance ...........0.10 through 0.18 ohmRecommended current

Testing ...................................< 50 milliamps Firing ............................................ > 10 amps Firing voltage.......................... 20 Vac or Vdc Electrostatic sensitivity............8 x 105 ergs at

400 micromicrofaradsBruceton data (typical) 50% line .....5.3 amps99.9% fire level (95% confidence) ..1.3 amps0.1% fire level (95% confidence) ....2.3 amps

5-3.5.7. Packing Data.Drawing 5166058.........................200 per drum

5-4. PERCUSSION PRIMERS Percussion primers require an initiating explo-

sive, or a mixture of such explosives, sensitive to the blow of a firing pin but insensitive to the shocks of ordinary handling. The smallest, simplest percussion primers are percussion caps. Other types of percussion primers are case percussion primers, case combination ignition primers, and lock combination primers. The combination primers are described in paragraph 6-5.

5-4.1. Percussion Caps. These are the simplest primers (Figure 5-6). They are used in small-cali-ber ammunition where they are press-fitted into the base of the cartridge; they are also a component of more complex primers for larger ammunition.

5-4.1.1. Description. A percussion cap consists of a brass or gilding metal cup containing a percus-sion-sensitive explosive mixture and a brass anvil. A typical mixture for a simple percussion cap con-sists of fulminate of mercury (initiating explosive), potassium chlorate (oxygen supplier), antimony sulfide (to prolong the flame), and ground glass (for friction).

5-4.1.2. Operation. When the cup is struck by a firing pin, the primer mixture is compressed between the cup and the anvil. Pressure and fric-tion initiate the explosive mixture. Flame passes through the flash vents in the anvil and through the flash hole to initiate the propellant powder. The sensitivity of this type of primer is determined by the amounts and proportions of the primer mixture, the pressure under which the mixture is loaded, and the thickness and type of metal in the cup and the anvil.

Figure 5-6 Percussion Cap Type Primer, Cutaway View

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5-4.2. Case Percussion Primer. The case per-cussion primer is used in ammunition for 76mm guns.

5-4.2.1. Description. This type (Figure 5-7) consists of a percussion cap to which is attached a perforated tube filled with black powder. Some case percussion primers contain a metal firing plug aft of the percussion cap to receive and direct the blow of the firing pin of the gun. Other primers of this type have the percussion cap located in the base surface. Also, primers of this type can have an ignition tube centrally located in the perforated primer tube. The ignition tube is filled with a finer grain of black powder than that in the primer tube. The burning of the black powder in the ignition tube ignites the black powder in the primer tube. Navy primers with the central ignition tube are no longer being procured. Current Navy primers only have black powder in the primer tube. The perfo-rations in the primer tube provide for a more even and widespread distribution of the flash from the black powder to the propellant. 5-4.2.2. Operation. The primer charge is ignited by the flash from the primer cap when the latter is struck by the firing pin of the gun.

5-4.3. Primer MK 22 MODs (Percussion).

5-4.3.1. General. This case percussion (press-fit) primer was developed to replace MK 21 Primer, which had performed unsatisfactorily. Consideration was given to adopting MK 19 Primer; however, it was found to be too small, and the firing plug construction was such that the firing pin travel in guns already in production was insuf-ficient to fire the primer. Tests performed on Army M23A2 Primer proved satisfactory, and it was adopted for use in 40mm ammunition with the des-ignation changed to MK 22 MOD 0. Preliminary acceptance tests revealed that the primer was more sensitive than the MK 21 when subjected to the rapid deceleration drop test. This resulted in the use of a conical washer made from 95-5 gilding metal placed between the firing plug and percus-sion element to act as a firing plug support or “dampening device.” This change was made before the primer was adapted for service so the designation MK 22 MOD 0 remained unchanged.

The performance of the MOD 0 was satisfactory except that it had a tendency to blow back. How-ever, by uniformly tapering the bearing surface of the primer stock and by manufacturing the primer from material somewhat harder than the cartridge case base, blowbacks were virtually eliminated. Therefore, this change was made and the designa-tion changed to MK 22 MOD 1. MODs 1 and 2 (Figure 5-8), along with the MOD 0, are now in current stocks of ammunition. They are service-able and ballistically, functionally, and dimension-ally interchangeable.

Figure 5-7 Typical Case Percussion Primer, Cutaway View

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5-4.3.2. Description. Primer MK 22 consists of a tapered, press-fit stock containing a percussion primer element and a brass primer tube containing 4.15 grams of class 2 black powder main charge. The MOD 1 differs from the MOD 0 in that the primer stock has been given a uniform taper, and the primer material is harder than the cartridge case base. The MOD 2 is identical to the MOD 1 except the primer stock throat diameter has been increased from 0.080 to 0.155 inch.

5-4.3.3. Interface.40mm ammunition


Overall length ............................ 3.205 inches Boss diameter MOD 0 ...................................... 0.615 inch MOD 1 ...................................... 0.619 inch MOD 2 ...................................... 0.619 inch Weight........................................ 0.106 pound

Thread dimensions............................Press-fit Primer tube

Length ...................................... 2.43 inches Unvented length ...................... 0.60 inch Vent diameter............................ 0.14 inch

No. of vents..........................................12 Components

Stock......................................................Brass Primer tube MOD 0, 1...........................................Brass MOD 2...................................Copper alloy Primer cap MOD 0.............................Drawing 281727 MOD 1.............................Drawing 281727 MOD 2..............Drawing 3028618 or M61

5-4.3.5. Explosive Data.Primer cap charge (FA-70)Lead sulfacyanate, potassium chlorate and

antimony sulfide...................... 65 milligramsPrimer tube

Class 2, black powder ..................4.15 grams

5-4.3.6. Functioning Data.Percussion sensitivity .................. 16 ounce ballAll fire................................................ 15 inchesNo fire.................................................. 4 inches

5-4.3.7. Packing Data.Inner pack ........................... 50 primers per boxOuter pack..................... 12 boxes per container

Figure 5-8 Primer MK 22 MODs 1 and 2 (Case Percussion), Cross-Sectional View

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5-4.4. Primer MK 161 MODs (Percussion).

5-4.4.1. General. This is a screw percussion primer designed for use in 76mm, 62 caliber (Oto Melara) fixed case ammunition. This primer was released for service use in 1977.

5-4.4.2. Description. The MK 161 MOD 0 Primer (Figure 5-9) uses a percussion element Military Primer 3208182, press-fitted into a steel stock and a seamless primer tube containing 18.1 grams of class 4 black powder. The holder and firing plug assembly contains a shear pin. This shear pin can be detected in the assembly and serves to prevent function during ramming. Shear pin presence is certified in the production of the primers by viewing the red shearpin through an inspection port.

5-4.4.3. Interface.76mm, 62 caliber ammunition


Overall length ..........................10.244 inches Boss diameter................................ 0.805 inch Weight........................................ 0.349 pound Thread dimensions.............0.619-20UNS-2A Primer tube Length ....................................9.252 inches Unvented length .....................2.362 inches

Vent diameter .............................0.167 inch No. of vents.............................................22Components

Stock.......................................................Steel Tube plug...................................Copper alloy Primer tube .............................................Steel Primer cap ........................................ Military

5-4.4.5. Explosive Data.Primer mix .............................................FA 956Primer tube

Class 4, black powder ..................18.1 grams

5-4.4.6. Functioning Data.Percussion sensitivity................... 24 ounce ballAll fire.................................H + 4S < 12 inches

(Bruceton Staircase)No fire ................................... H – 2S ± 2 inches

(Bruceton Staircase)

5-4.4.7. Packing Data.Drawing 2645160 .... 120 primers per containerDrawing 2645488 .........................Palletization,

20 containers per pallet

5-5. COMBINATION PRIMERS Combination primers may be initiated by elec-

trical means or by percussive means.

Figure 5-9 Primer MK 161 MOD 0 (Percussion), Cross-Sectional View

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5-5.1. Primer MK 15 MODs (Lock Combina-tion).

5-5.1.1. General. Primers in the MK 15 series were developed to provide a combination electric and percussion primer for use in bag guns but are now used as a test primer only. The MOD 1 is sim-ilar to the MOD 2 (Figure 5-10) except that the MOD 1 has a Winchester cap No. 2-1/2, the same as the MODs 3 and 4, and the MOD 1 is the only MOD without lead styphnate applied to the bridgewire. The MK 15 MOD 2 originally had an electrical bridgewire surrounded with a wisp of long-fiber guncotton. To reduce the latent time of firing, a dab of lead styphnate was applied to the bridgewire. All MOD 2s produced since August 1954 have been processed accordingly. No addi-tional MOD number has been assigned for this change. MODs 1, 3, and 4 are inactive, and no fur-ther production is anticipated. The MOD 2 is cur-rent and serviceable but is being replaced as a 5-inch circuit tester by an electronic circuit tester which is reusable (see paragraph 5-6.1.).

5-5.1.2. Description. The MK 15 Primer consists of a tapered stock containing a percussion electric ignition element and about 1.944 grams of Class 4 black powder main charge. The MOD 2 uses the ignition element developed for the MK 13 MOD 2 Primer modified as previously described. This ignition element uses a No. 34 cap for percussion firing. The electric element consists of

a dab of lead styphnate and a wisp of guncotton on a single 0.002-inch-diameter platinum-iridium bridgewire with a booster charge of black powder and pyrocellulose. The main charge is contained in a brass thimble with an embossed end to allow uniform opening. The addition of lead styphnate to the bridgewire was the major change from the MOD 1 to the MOD 2. This change was made to improve electrical function reliability. The MOD 3 differs from the MOD 2 in that the electrical element consists of a lead styphnate charge buttered around a double-arm 0.002-inch diameter platinum-iridium bridgewire and its resistance is lower. It functions the same as the MOD 2 in single fire but, because of its low resistance, will not function properly when used with delay coils. The MOD 4 has the same ignition element as the MOD 3 but its main charge is loaded directly into the stock instead of using a separately loaded thimble.

5-5.1.3. Operation. The small amount of black powder contained in the primer can furnish both audible and visual evidence of the functioning of the gun firing circuit when the firing current is applied to the ignition element.

5-5.1.4. Interface.5-inch and 3-inch 50 caliber test cartridges

Figure 5-10 Primer MK 15 MOD 2 (Lock Combination), Cross-Sectional View

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Overall length ..............................1.99 inches Boss diameter................................ 0.596 inch Weight ......................................... 0.06 pound Thread dimensions............................Press-fitComponents

Stock MOD 1 ............................................... Brass MOD 2................................................ Brass MOD 3 ................................................ Brass MOD 4 ................................................. Steel Thimble ................................................. Brass Ignition element MOD 1............................. Drawing 437780 MOD 2 ........................... Drawing 2846997 MOD 3 ........................... Drawing 1410962 MOD 4 ........................... Drawing 1410962

5-5.1.6. Explosive Data.Percussion

Winchester cap MOD 1.........................................No. 2-1/2 MOD 2............................................. No. 34 MOD 3 ........................................No. 2-1/2 MOD 4.........................................No. 2-1/2Electrical

Guncotton MOD 1 .................................12 milligrams MOD 2..................................12 milligrams MOD 3............................................... None MOD 4............................................... None

Lead styphnate MOD 1 .............................................. None MOD 2................................................. Dab MOD 3..................................34 milligrams MOD 4..................................34 milligrams

Booster, class 6 black powder-nitrocellulose MOD 1..................................18 milligrams MOD 2..................................18 milligrams MOD 3............................................... None

MOD 4 ...............................................NoneCharge, class 4 black powder

MOD 1 ......................................1.94 grams MOD 2 ......................................1.94 grams MOD 3 ......................................2.07 grams MOD 4 ......................................2.20 grams

5-5.1.7. Functioning Data.Primer resistance

MOD 1 ................................ 0.55 – 0.70 ohm MOD 2 ................................ 0.55 – 0.70 ohm MOD 3 ................................ 0.08 – 0.14 ohm MOD 4 ................................ 0.08 – 0.20 ohmRecommended current

Testing ................................... < 50 milliamps Firing .............................................> 10 ampsFiring voltage ..........................20 Vac or Vdc

Electrostatic sensitivityMOD 1 .....................................................NAMOD 2 ....................................................NA

MOD 3 ..........................1.5 x 106 ergs at 400micromicrofarads

MOD 4 ...........................1.5 x 106 ergs at 400micromicrofarads

Percussion sensitivity................... 16 ounce ballAll fire................................................ 10 inchesNo fire .................................................. 3 inches

5-5.1.7.1. Packing Data.Drawing 1251320 .......................Inner pack, 38

primers per canDrawing 2846999 ..............Outer pack, 32 cans

per containerNo palletization standard established

5-6. FIRING CIRCUIT TEST The firing circuit of some gun mounts can be

checked without expending a full, reduced, or clearing charge. The MK 15 primer has been used in a special adapter to test the firing circuit in 5-inch guns (see paragraph 5-5.1.). The MK 55 Elec-tronic Firing Circuit Tester provides an improved method for testing the firing circuit of a 5-inch gun.

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5-6.1. MK 55 MOD 0 Electronic Firing Circuit Tester (EFCT).

5-6.1.1. General. The MK 55 MOD 0 Elec-tronic Firing circuit Tester (EFCT) is not an elec-tric primer, but is a clearing charge sized 5-inch 54 caliber firing circuit tester. The EFCT is described here (see Figure 5-11) since it is replacing the MK 15 MOD 2 primer (see paragraph 5-5.1.) as a circuit tester for 5-inch guns.

5-6.1.2. Description. The EFCT components are contained in a shortened 5-inch cartridge case and is totally inert. Instead of an audible noise as is obtained with using the MK 15 MOD 2 primer, the EFCT provides a visual light signal in two ways. First, if the firing circuit has the proper current to reliably initiate a MOD 15 MOD 2 primer, a signal will be sent to the EP2 panel, blinking the misfire light twice. If the circuit is bad, the misfire light will blink once or not at all. And then, when the EFCT is removed, a green light on the tester will indicate a good circuit and a red light a bad circuit. Also, AC and DC current will be indicated. Up to four tests can be conducted in one cycle of the EFCT.

5-6.1.3. Operation. The EFCT is loaded at the Upper Hoist station into the 5-inch 54 gun mount ammunition handling system. The EFCT is then hoisted and rammed in the gun chamber and the breech is closed. The gun is "fired" using the

remote, GMCP, local and emergency circuits. If a minimum of 16 volts and 10 amps are applied a good circuit will be indicated by blinking the mis-fire light twice and displaying a green light on the tester. If 5 to 16 volts applied or less than 10 amps are applied a bad circuit will be indicated by one blink of the misfire light and displaying a red light on the EFCT. If less than 5 volts are applied the EFCT will indicate a no test by not blinking the misfire light and no lights will be illuminated. Also a yellow AC or DC light indicates AC current or DC current (from emergency circuit using bat-tery power) was used. After testing the EFCT is extracted from the chamber and the EFCT is manu-ally retrieved from the gun mount.

5-6.1.4. Interface. 5-inch, 54 caliber.

5-6.1.5. Functioning Data.Good circuit: 16 volt min. and 10 amp min.Bad circuit: 5 to 16 volts at any current or

5 volts min. at less than 10 ampsNo test: Less than 5 volts at any current

5-6.1.6. Reference.Part number: 7263274National Stock Number: 1H 6625-01-443-1864Allowable Equipment List: 0-006040002

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Figure 5-11 MK 55 MOD 0 Electronic Firing Circuit Tester

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CHAPTER 6

EXPLOSIVES

6-1. INTRODUCTION This chapter covers explosives as they apply to

Navy gun-type ammunition. Explosives are materi-als that store large quantities of chemical energy, releasing it very quickly upon the correct stimulus, to perform the functions required of the ordnance, such as propelling the projectile or exploding the warhead. Explosives are categorized as propel-lants or high explosives. Both have similar chemi-cal compositions, and they can be made to react at similar rates. What differentiates a propellant and a high explosive is that the propellant is designed to burn at a high, reproducible rate that is below the rate of detonation, while a high explosive does its work through detonating. Given the correct condi-tions, propellants can be made to detonate and high explosives can burn, but their intended functional mode is what distinguishes one from the other.

6-2. PROPELLANT

6-2.1. Introduction. The propellant is the major active component of the propelling charge and is contained in a cartridge case. It starts to burn when the primer functions. The primer contains a small amount of igniter material, a very fast burning pro-pellant which is easier to initiate than the main pro-pellant charge. The propellant burns at a high, reproducible rate, generating a large volume of gas for a relatively small volume of solid material burned. This generation of gas, when confined in the breech and barrel of the gun, causes high pres-sure to build up, providing the propulsive force for the projectile.

6-2.2. Background. The invention of gunpow-der is traditionally credited to Friar Francis Bacon who lived in the thirteenth century, although Chi-nese legends hint at an earlier date in that land. Gunpowder as it was first used was essentially equal parts of charcoal, sulfur, and potassium nitrate (also known as nitre or saltpeter). The rec-ipe for black powder, as we now call it, has evolved to be 75 percent potassium nitrate, 15 per-cent charcoal, and 10 percent sulfur. Until the late 1880’s black powder was the primary gun propel-lant.

6-2.2.1. Black Powder. Soldiers who used black powder were admonished to “keep your powder dry!” for good reason. In the presence of moisture, black powder deteriorated so that its per-formance was unpredictable, although kept dry it maintained its properties almost indefinitely. Guns required frequent cleaning to avoid fouling caused by the residue left by the black powder, and the erosion caused by its use meant that barrels wore out quickly. Firings yielded vast amounts of smoke that obscured vision. Black powder is quite sensitive to friction, sparks, and heat. The ballistic reproducibility that can be achieved with black powder is rather low. Clearly, if gunnery were to advance, a replacement to black powder had to be found.

6-2.2.2. Nitrocellulose. Nitrocellulose (NC) was first prepared in 1838, and its potential as a propellant was soon recognized. NC is a fibrous white powder and is fairly fluffy. As such, it is not a very good propellant since not much can be put into the gun and it is hard to control the rate at which gas is generated. Yet, it burns cleanly, pro-duces little smoke, and is safer to handle than black powder, so work to make NC a viable propellant continued. In 1886, Vieille colloided (or gelati-nized) NC with alcohol and ether to make a denser material whose burning properties were much eas-ier to control. This was the first smokeless powder and ushered in a new era in gun propellants. Fur-ther refinements included the addition of stabilizers to increase the safe storage life of the propellant, the use of flash suppressants, the incorporation of additives to reduce the hygroscopicity (tendency to absorb water) of the propellant, the reduction of the flame temperature (thus increasing barrel life), and even to increase the energy available from the pro-pellant. Today, NC remains the basis of almost every gun propellant in use.

6-2.3. Smokeless Powder. Smokeless powder is the term used to refer to the gun propellant used in propelling charges for gun ammunition. In appear-ance, most propellant is in the form of right circu-lar cylinders with zero, one, or seven perforations running parallel to the axis of the cylinder. Some

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propellants for smaller caliber guns take the form of slightly flattened balls called, appropriately enough, Ball Powder®. The shape, or granulation, of the propellant is designed to present a controlled burning surface area. It is through the granulation that the rate of gas generation, and therefore pres-surization, is controlled. Most smokeless powder formulations are primarily colloided NC to which has been added as a stabilizer such as diphenylam-ine, 2-nitrodiphenylamine, ethyl centralite or akardite. The addition of the stabilizer is necessary to prevent the products of the naturally-occurring decomposition of the NC from accumulating and accelerating the decomposition. Unchecked, such accelerated decomposition can lead to ignition. The stabilizer interrupts this chain by reacting with the initial decomposition products. This reaction, while it prevents accelerating decomposition, decreases the stabilizing capacity of the propellant. The rate at which the initial decomposition of NC takes place is dependent upon temperature and humidity, with high temperature and humidity causing faster decomposition. Under the best of conditions, over time, the stabilizer is depleted, and the propellant is no longer safe to handle. Surveil-lance testing is done to predict the safe handling life of the propellant and to ensure that propellants are removed from the inventory before they are unsafe. See SW020-AE-SAF-010, Technical Man-ual for Safety Surveillance of Navy Gun Propellant for additional information.

6-2.3.1. Classification of Smokeless Powder. Smokeless powders are of three types: single-base, double-base, and triple-base.

6-2.3.2. Single-Base Powder. This type of powder comprises the bulk of the Navy inventory and refers to a propellant whose only energetic ingredient is NC to which a stabilizer has been added. Other materials may be incorporated into the formulation as described in 6-2.3.3. and 6-2.3.4. Grains of single-base powder are hard, have a translucent off-white color when new, and may be graphite coated to improve loading.

NOTEWith age, the color of single-base grains becomes darker, finally becoming opaque. The change in color does not in itself indicate any loss of stability or per-formance.

6-2.3.3. Double-Base Powder. Existing in the Navy inventory only in small-caliber ammunition, double-base powder consists of NC plasticized with nitroglycerin (NG). The addition of NG raises the energy of the propellant and makes the propel-lant even tougher. The powder may be small seven-perforated grains or Ball Powder®, which looks like tiny, flattened spheres. Both are coated with graphite, which gives them a shiny, dark gray surface.

6-2.3.4. Triple-Base Powder. Nitroguanidine (NQ), a white, crystalline solid, is added to NC and NG to produce triple-base powder. The NQ increases the energy density, while lowering the flame temperature of the propellant.

6-2.4. Index of Smokeless Powder. Each lot of propellant accepted from the manufacturer for loading into large caliber ammunition is assigned a propellant index. Smokeless powder types are assigned class designation letters that indicate the chemical components of the powder, as follows:

SP – Smokeless powderB – BlendedC – Stabilized by ethyl centraliteD – Stabilized by diphenylamineF – FlashlessG – Includes nitroglycerin and nitroguani-

dineN – NonhygroscopicW – Reworked by grindingX – Water-drying process

These letters are followed by a number that indi-cates the sequence of lot acceptance. The combina-tion of letters and number are the index of the powder. Powder which is procured already loaded into ammunition (such as that for the small-caliber

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ammunition) is not assigned an index number. The various possible class designations are described as follows:

a. SPC – cool burning, single-base smokeless powder (SP) with ethyl centralite (C) added as a stabilizer.

b. SPCF – single-base smokeless powder, similar to SPC-type powder, but containing a flash suppressor (F) to render the powder flashless. NACO is the primary example of SPCF.

c. SPCG – smokeless powder (SP), stabilized by ethyl centralite (C), of the triple-base, or nitro-glycerin and nitroguanidine-containing type (G). While SPCG is a flashless powder, containing flash suppressant, the letter “F” is not used. Cordite-N is the only SPCG propellant in the Navy inventory.

d. SPD – single-base powder (SP), stabilized through the addition of diphenylamine (D). Pyro is the prime example of SPD.

e. SPDB – diphenylamine-stabilized smoke-less powders (SPD) that have been blended (B). The purpose of blending is to provide a uniform index of ample size and performance from smaller lots.

f. SPDF – diphenylamine-stabilized smoke-less powder (SPD) that has a flash suppressant (commonly potassium sulfate) (F) added. In all powder currently being manufactured, the flash suppressant is incorporated into the propellant. For some older 5-inch, 38 caliber rounds, the flash sup-pressant is pelletized and added to the charge sepa-rately. The flash suppressant is sometimes referred to as “salt.” Propellant that contains the flash sup-pressant in its formulation performs better; there-fore, any ammunition of the older sort, incorporating salt pellets, should be used in target practice and training exercises. The salt pellets can leave a residue in the gun, necessitating more fre-quent inspections and cleaning when rounds incor-porating them have been fired.

g. SPDN – diphenylamine-stabilized smoke-less powder (SPD) to which has been added mate-rial to reduce its hygroscopicity (N). This designation is also used for blends of such pow-ders. M6 + 2 is one of the SPDN powders.

h. SPDW – diphenylamine-stabilized smoke-less powder (SPD) that has been reworked (W) by grinding and the addition of more stabilizer to pro-duce new stabilized grains. This type is generally used for target practice and reduced charges.

i. SPDX – diphenylamine-stabilized smoke-less powder (SPD) that is water dried (X). In the water-drying process, the powder is held in tanks of heated water to drive off volatile processing sol-vents, then air-dried.

j. SPWF – smokeless powder (SP) made by reworking (W) and addition of flash suppressant (F).

6-2.5. Black Powder.

6-2.5.1. Description. Black powder is a propel-lant, though its use in the Navy is limited to ignit-ers, expelling charges, a delay element and sometimes a magazine element in fuzes, a noise-maker in saluting charges, and a propellant for impulse charges. In its primary function as an igniter material, it is loaded into primer tubes for cased charges. Its characteristic of having a burn rate which is nearly independent of pressure makes it a good match for these uses.

6-2.5.2. Classes of Black Powder. The appear-ance of black powder is adequately described by its name. The granulation of the powder is varied to accomplish the purpose for which it may be employed. Generally, the finer the granulation, the more rapidly is pressure developed in the combus-tion. Various granulations of black powder are used in loading gun ammunition components such as fuzes, saluting charges, primers, and expelling charges. Formerly designated by grades, granula-tion size is now designated by class (determined by a process using U.S. standard sieves) as follows:

GRADE (OLD SYSTEM)

CLASS (NEW SYSTEM)

Cannon 2

Musket 4

FFG 4

Shell 6

FFFG 6

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6-2.6. Grain Geometry. The burning character-istics of a propellant formulation, the pressure at which it is burning, and the surface area history of a granulation are what determine the rate at which gas is produced. The burning characteristics of a propellant are determined by the formulation, and the manner in which the propellant is processed, and the pressure is a function of the gun parame-ters, which leaves the surface area as the only fac-tor through which we can control the pressure history in the gun. For a given weight of propel-lant, large grains will have a smaller total surface area, therefore less surface burning and generating gas. The pressure rise from large grains will be slower than for small grains, and likewise grains with more perforations will yield faster pressure rises than those with few perforations. The size and shape of the grain must be carefully matched to the gun performance. If the grains are too small and so generate gas too quickly, overpressurizing the gun can result. If the grains are too large, they may not burn out completely before the projectile exits the muzzle and so yield less than optimal per-formance. Grain size is typically discussed in terms of the web. The web is the distance between two adjacent burning surfaces and is illustrated for single- and seven-perforated grains in Figure 6-1. Table 6-1 gives examples of some typical grain sizes for various gun systems.

6-2.7. Interior Ballistics. Interior ballistics refers to the phenomena that occur inside the gun between the moment the primer is initiated until the projectile exits the muzzle. It encompasses the spreading of flame from the primer to the propel-lant in the immediate vicinity of the primer tube, the flamespread from localized areas to burning throughout the charge, the accompanying pressure rise as gas builds up, then the subsequent pressure decrease as the projectile starts to move down the barrel. The most important tool of the interior bal-listician is the pressure-time curve. A typical one is shown in Figure 6-2. By noting the maximum pressure achieved, the rate of pressure rise and fall and the smoothness of the curve, the burning his-tory of the charge can be deduced. The charge designer seeks to optimize the shape of this curve to achieve the most efficient, most reproducible, and safest performance possible from the gun sys-tem.

6-3. HIGH EXPLOSIVES A high explosive is a substance or device

which, when initiated, will release its energy very rapidly. This release is usually in the form of high temperatures and large volumes of gas and creates high pressures on the surrounding areas very sud-denly. Military high explosives are chemical com-pounds that are able to decompose extremely fast. This extremely rapid reaction rate of approxi-mately 7,000 meters per second accompanied by the evolution of a large gas volume, heat, noise, and a widespread shattering effect, is called a

Fuze 7

FFFFG 7

Meal 8

Figure 6-1 Propellant Grain Web Locations

GRADE (OLD SYSTEM)

CLASS (NEW SYSTEM)

Figure 6-2 Pressure-Travel Curve

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“detonation.” High explosives usually contain nitrated products of organic compounds. A few specialized explosives are compounded from heavy metals such as lead mercury and either organic materials or nitrogen itself in the form of nitride salts. A high explosive may be a pure com-pound or an intimate mixture of several com-pounds. Other ingredients such as wax or aluminum that impart desired stability and/or spe-cific performance characteristics may also be added.

6-3.1. Classification of High Explosives. High explosives are divided into two categories – pri-mary explosives and secondary explosives.

6-3.2. Primary Explosives. Primary explosives are highly sensitive and are easily initiated by heat, impact, or friction. They invariably react to stimulus by detonating as opposed to simple burning. This is their most distinctive characteristic. Primary explosives do not have a high level of explosive power but because of their sensitivity are generally used to initiate more powerful booster explosives.

6-3.3. Secondary Explosives. Secondary explo-sives include both booster and main charge explo-sives. Both are considered less sensitive than primary explosives with the booster or intermedi-

ate explosive lying somewhere between the very sensitive primary explosives and the relatively insensitive main charge explosives.

6-3.4. Use in Gun Ammunition. All gun ammunition, 20mm or larger, contains a high explosive burster (main) charge which is detonated at the target by an appropriate fuzing system. Navy gun ammunition is composed of a fuze, an auxil-iary detonating (AD) fuze (not always used), and a main charge. The fuze (including the AD fuze) contains one or more detonators, one or more leads, and a booster. All of these components con-tain high explosives, and in a projectile the arrangement of the components is called an explo-sive train. Redundant detonators and leads give increased functional reliability. A typical explosive train consists of a detonator, a lead, a booster, and a main charge. The detonator is usually initiated either by the action of a sharp pointed firing pin or by passing an electric current through a fine wire coated with explosive. The detonator, as its name implies, rapidly goes from a deflagration to a deto-nation and transfers the detonation shock wave to a booster explosive (or lead) which is generally about the size of a pencil eraser. The purpose of the lead is to amplify the detonation shock wave and transfer it to a larger booster explosive where it is stabilized sufficiently to assure full detonation of the main explosive charge. These various elements are discussed in detail in the following paragraphs.

Table 6-1 Relative Grain Sizes by Gun Caliber

Gun Size Number of Perforations

GrainLength (in.)

Grain Diameter (in.)

Perforation Diameter (in.) Web Thickness (in.)

20mm 1 0.10 0.04 0.008 0.017

25mm 1 0.06 0.04 0.006 0.020

30mm Proprietary Information

40mm 7 0.30 0.12 0.013 0.020

57mm Proprietary Information

76mm 7 0.67 0.30 0.035 0.049

5-in, 54-cal 7 0.76 0.32 0.031 0.058

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6-3.5. Detonators. Detonators are used in fuzes or auxiliary detonating fuzes and contain primary explosives. Since they do contain these very sensi-tive primary explosives, they are installed in a mechanism that is deliberately misaligned with the explosive train during production, handling, and storage. Misalignment is maintained until gun fir-ing and even then until such time as the projectile moves a safe distance away from the gun. This assures prevention of propagation of the detonation to the main charge in case of an accidental fuze ini-tiation. In the event of an accidental initiation in the misaligned mode, the surrounding hardware is designed to contain the detonator output to prevent injury to personnel or equipment and to prevent initiation of other parts of the explosive train. A gun firing a projectile introduces forces that mechanically allow the detonator to align itself with the other elements in the explosive train after the projectile has left the gun. The armed fuze is now ready to initiate the main explosive charge upon target impact. Although a number of differ-ent explosives and mixtures of explosives are used in detonators, the following paragraphs describe those most widely used. Their properties are typi-cal of other primary explosive materials.

6-3.5.1. Description. Generally a detonator, either stab or electrically initiated, is composed of three parts: an initial charge, an intermediate charge, and a base charge. The initial charge is acti-vated by a relatively small, mechanical or short, but intense, electrical heat stimulus to produce a self-propagating reaction. The output of the initial charge consists principally of relatively low veloc-ity hot gases and particles that are propelled against the intermediate charge. Transition from burning

to detonation takes place in the intermediate charge. The base charge intensifies the shock from the intermediate charge sufficiently to transfer it to the next element in the train.

6-3.6. Leads and Boosters. Leads and boosters are those components of the explosive train whose function is the transmission of the detonation established by the detonator and the augmentation of the detonation to a level such that the main or burster charge is initiated reliably. Booster explo-sives in general are more sensitive than main charge explosives but still much less sensitive than primary explosives.

6-3.7. Burster or Main Charge Explosives. The main or burster charge in a projectile provides the explosive force to fragment the case and destroy or damage a target. The explosive for the burster charge is selected for safety, performance, and cost. A large portion of Navy gun ammunition uses explosive powders that are press-loaded into the case. The largest proportion of 5-inch gun ammunition is loaded with Composition A-3, a rel-atively powerful explosive. The current inventory of 76mm projectiles are loaded with composition A-3 as well, although the latest approved design replaces composition A-3 with a cast-cured plastic-bonded explosive. 20MM ammunition is loaded with tetryl. 40MM ammunition when last loaded used pressed comp A-3. The 5-inch, 54 caliber HI-FRAG round and the more recent 5-inch, 54 cali-ber MK 64 design are loaded with a cast-cured plastic-bonded explosive, PBXN-106. The most recent 5-inch, 54 caliber MK 64 design replaces PBXN-106 with PBXN-9, a pressed plastic-bonded explosive.

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APPENDIX A

HISTORICAL DATA

A-1. GENERAL Ammunition assemblies and primers for 5-, 6-, 8-, and 16-inch guns that are no longer in use are pro-vided in this appendix for information only.

A-1.1. Inspection Prior to Use.Gas Check Seal Inspection Criteria for Projec-

tiles Assembled with Base Fuzes/Base Fuze Hole plugs/Base Plugs

A-1.1.1. Introduction.

ALL PROJECTILES FITTED WITH GAS CHECK SEALS MUST BE THOROUGHLY INSPECTED BY SHIP PERSONNEL PRIOR TO USE TO ENSURE THE PRESENCE OF, AND CONTINUITY OF, THE GAS CHECK SEAL. ANY PROJECTILE FOUND TO HAVE A MISSING, FAULTY, OR DAMAGED GAS CHECK SEAL SHALL BE REJECTED.

In any projectile with a base plug, base fuze, or both, great care is required to ensure threaded joints are sealed to prevent leakage of hot gases from the burning propellant from penetrating into the explosive cavity of the projectile body. Copper and lead rings, known as gas check seals (GCSs), are pressed into special grooves containing the joint under heavy hydraulic pressure to form a gas tight seal.

A-1.1.2. Background. Improperly installed GCSs may have caused premature in-bore and close-aboard firings by permitting hot gases to enter the explosive filler area of the projectiles. This suspicion has caused stringent inspection requirements to be placed on the fleet and field

activities concerning the possibility of improperly installed GCSs. Test firings have shown that a combination of the following defects could cause premature firing:

a. Unseated base fuze or plug

b. Loose fit threads

c. Inadequate luting

d. Explosive in threads

e. Missing gas check seal.Tests demonstrated also that if the first four

deficiencies were present together in one projectile in gross degree, a good GCS would provide protec-tion against an in-bore premature firing. Since the more stringent inspections, premature firings basi-cally have been eliminated.

NOTEAmmunition suspended by the applica-tion of pre-1970 GCS inspection criteria is to be held for GCS removal and replacement or other disposition as directed.

A-1.1.3. Procedures to be Used when Install-ing Gas Check Seal or for Pre-1970 (Unin-spected, Unsuffixed) Loaded Ammunition. The following procedures for GCS inspection shall be used when installing GCSs or for pre-1970 (unin-spected, unsuffixed) loaded ammunition. If the pre-1970 ammunition items meet the criteria below, the appropriate suffix shall be placed after the ammunition lot number, according to the appli-cable notes of NAVSUP P-801.

NOTEUninspected and unsuffixed ammunition produced prior to 1970 shall have the paint removed from the gas check seal before the inspection. Paint may be replaced after the inspection.

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A-1.1.3.1. Mandatory Gas Check Seal Proce-dures. The following are mandatory GCS proce-dures for an acceptable product (Figure A-1):

a. Check that the complete GCS (copper ring and lead core) is present and base fuze/base fuze hole plug is flush with or below the base of the pro-jectile.

b. Check that the GCS is properly installed (copper ring covers and protects lead core).

c. Check that the complete GCS is properly pressed in place (that the GCS has been pressed with adequate pressure to ensure tight fit and expansion of copper and lead in dove-tailed coun-terbore area between projectile base and base fuze/base fuze hold plug).

d. Check that the GCS, including roll-up, is flush with or below the projectile base and base fuze/base fuze hold plug. (Roll-up of copper around pressed surface on either or both sides of tool indentation is acceptable and to be expected.)

e. Check that the copper ring is free of cuts, tears, gouges, or foreign material.

NOTEThe procedures and criteria presented in Paragraphs A-1.1.3.1. through A-1.1.4.cancel and supersede the guideline data previously provided. Gas check display kits are to be returned to Crane Division, Naval Surface Warfare Center (NAV-SURFWARCENDIV CRANE), Crane, Indiana. The criteria presented are not appropriate for ship-board GCS inspec-

tion nor for the inspection of fleet return, fleet issue, preshipment, and segregation of post-1970 production or pre-1970 properly suffixed ammunition.

A-1.1.3.2. Acceptable Gas Check Seal Condi-tions. Provided the requirements of Paragraph A-1.1.3.1. are met, the following additional GCS con-ditions are acceptable:

a. Slight gap between the copper ring and projectile base and/or base fuze/base fuze hole plug. (See Figure A-2.)

b. Multiple (more than one) pressing of the GCS provided the copper ring is not broken. (See Figure A-3.)

c. GCS is canted (not evenly seated around entire pressed surface). (See Figure A-4.)

Figure A-1 Mandatory Gas Check Seal Requirements for Acceptable Product

Figure A-2 Slight Gap Around Gas Check Seal - Acceptable Condition

Figure A-3 Multiple Press of Gas Check Seal - Acceptable Condition

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d. Slight deformation in copper ring provided it is not broken (attributable to hand gas checking operations, damaged seating tool, or other minor damage that induced the deformation during the pressing or handling operations).

e. Globules of luting on or around the GCS. (Luting is light brown in color and may be miscon-strued as trinitrotoluene (TNT) exudation.)

A-1.1.3.3. Unacceptable Gas Check Seal Con-ditions. The following GCS conditions are unac-ceptable:

a. Entire GCS (copper ring and lead core) is missing. (See Figure A-5.)

b. GCS is inverted (lead core pressed in on top of copper ring). (See Figure A-6.)

c. Lead core is missing (evidenced by copper ring being seated excessively deep—approxi-mately 3/32 inch). (See Figure A-7.)

d. GCS is not fully and properly seated. (This is caused by insufficient pressing force or improper tooling – evidenced by copper ring not being flat-tened and seated.) (See Figure A-8.)

e. Any part of the GCS, including copper roll-up, is above either the projectile base or base fuze/base fuze hole plug. (See Figure A-9.)

f. GCS is cut, torn, or gouged, exposing the lead core. (The most common cause of a cut or tear is excessive pressing pressure, and the most logical location of a cut or tear is around the outer periphery of GCS at the 90-degree angle of cop-per.) (See Figure A-10.)

Figure A-4 Canted Gas Check Seal - Acceptable Condition

Figure A-5 Entire Gas Check Seal Missing - Unacceptable Condition

Figure A-6 Inverted Gas Check Seal - Unacceptable Condition

Figure A-7 Missing Lead Core - Unacceptable Condition

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A-1.1.4. Fleet Inspection Procedures for Pro-jectile Gas Check Seals Subsequent to Issue. Fleet users shall check for damage to GCSs that may have occurred during handling, transportation, and storage subsequent to issue by an ammunition activity to ensure that:

a. GCS is not missing.

b. GCS is free of cuts, tears, or gouges that expose the lead core.

c. GCS is flush with or below base fuze or plug surface.

Ammunition with any of the defects noted from the above inspection procedures should be marked as defective and should be turned in as soon as possible. A message report should be made to COMNAVSEA, with copies to the Naval Weapons Station (WQEC), Concord, California, and the NAVSEA, PM NCAS Program Mgt Office, Picatinny Arsenal, NJ, giving ammunition lot identification, nature of defect, and any back-ground information on the cause if available.

NOTEInasmuch as certain fleet units handle palletized ammunition, they are not expected to depalletize and inspect GCS in accordance with the instructions of Paragraph A-1.1.4. The use of NAV-SURFWARCENDIV CRANE GCS dis-play kits for shipboard inspection of ammunition is not appropriate. Ship-board removal of paint from projectiles is not authorized.

A-2. SEPARATE LOADED AMMUNITION

A-2.1. Bag Charge. In large guns using separate loading ammunition (Figure A-11), the propellant charge is made up of sections of powder contained in cylindrical cloth bags that approximate the inside diameter of the gun chamber in which they are used. In a full charge, the propellant grains are stacked in the charge with the bag laced tightly around them. A reduced charge is one in which the propellant grains are dumped into the bag. The bag is not as tight as a full charge and is smaller in diameter. In most cases, more than one section (bag) is required. For example, the 8-inch, 55 cali-ber gun uses a propellant charge consisting of two sections, while the 16-inch, 50 caliber gun uses a

Figure A-8 Gas Check Seal Not Fully or Properly Seated - Unacceptable Condition

Figure A-9 Gas Check Seal Seated Above Either or Both Projectile Base and Fuze/Plug

Unacceptable Condition

Figure A-10 Torn, Cut or Gouged Gas Check Seal - Unacceptable Condition

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propellant charge of six sections. In these guns the leaking of gases from the chamber is checked by the mushroom and pads on the breech plug. The breech plug also contains a firing lock attached that receives the separately loaded primer.

A-2.2. Bag Material. The bags are made of cloth that is entirely consumed in the burning of the powder. It is woven closely enough to contain dusty powder and at the same time to be permeable to flash. It is free from acids that might react with the powder and is also able to withstand acid chem-ical reactions from the powder itself. The bags are secured by laces and are provided with a strap of the same material as the bag for handling.

A-2.3. Ignition End. The aft end of each bag consists of red-colored quilted pocket containing a charge of black powder. The cloth used on this end

is a lighter weight than that used on the body in order to permit quick penetration by the flash from the primer. The firing of the primer in bag guns ignites the black powder in the ignition pad, which in turn ignites the smokeless powder. Thus each additional bag of a charge must be loaded with the ignition pad aft and within a few inches of the next bag or of the breech plug. This condition requires that the total length of the powder bags comprising a charge must be nearly equal to the length of the chamber in the gun. When a reduced charge is pro-duced, the number of powder bags is unchanged. The diameter of the aft ends (ignition ends) of the bags cannot be materially reduced without risking failure in the ignition process.

Figure A-11 Separate Loaded Bag Charge

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A-2.4. Loading. Bag charges are either dump or stack loaded (Figure A-12). In dump loading, the powder, after being weighed, is dumped loosely into the bag. The bag is then rolled and tightly laced. For large caliber guns, stacked bags have replaced dump-loaded bags except in the reduced charge. Stacking places the powder grains on end in layers so that a tight, uniform charge is obtained. Since propulsive powder may vary between indexes of smokeless powder, bag charges are assembled by specific weights of a particular pow-der index. The complete service ammunition allowance for a ship is normally made from a sin-gle powder index to provide uniformity in ballistic character. Hence bag charges do not receive mark and MOD designations; the variation is mainly in the powder itself. The dimensions of the bag charges in any particular ammunition lot are deter-mined after loading a sample charge into a bag.

A-2.5. Classification of Bag Charges. The term “service charge” is no longer used in connection with bagged ammunition. The current designa-tions of bag charges are as follows:

a. Full charge—for use with HC or AP pro-jectiles at full velocity and/or service pressure.

b. Reduced charge—for use with HC or AP projectiles at reduced velocity and chamber pres-sure.

c. Special charge—any charges other than full or reduced.

A-3. AMMUNITION

A-3.1. 40 Millimeter Ammunition.


A-3.1.1. General. This section describes char-acteristics of all of the 40mm ammunition car-tridges currently in the Navy 2T cog inventory except for the 40mm grenade cartridges listed in SW010-AD-GTP-010. The 40mm ammunition is issued in the form of a "fixed" or completely assembled cartridge in which the cartridge case is crimped around the base of the projectile. This arrangement permits handling of the projectile and propelling charge as one unit. The 40mm cartridge is used in a rapid-fire, automatic gun, fed by an automatic mechanism into which four-round char-ger clips are hand-loaded. The gun can be fired in a rapid-fire or single-shot mode. This system is used as defense against light aircraft or surface tar-gets. The cartridges are identified and issued as follows:

Figure A-12 Bag Charges: Stacked and Dumped


Armor-piercing AP B551Armor-piercing, tracer

AP-T B552

High explosive incendiary, plugged, dummy nose plug

HEI-P-NP B556

High explosive incendiary, self-destruct

HEI-SD B557

High explosive incendiary tracer, non-self destruct

HEIT-NSD B558

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A-3.1.2. Ammunition/Interface. The 40mm service cartridges are used in the following gun mounts:

A-3.1.3. The 40mm blank saluting charges are used in the MK 11 saluting gun mount.

A-3.1.4. Ammunition Characteristics. The shape, weight, and ballistics of all of the 40mm ser-vice cartridges are approximately the same. The ammunition functions in the following sequence:

a. The firing pin of the gun strikes the percus-sion primer and ignites the black powder in the primer tube.

b. Sparks from the black powder ignite the propellant to impart velocity to the projectile and to ignite the tracer.

c. The fuze detonates the high-explosive filler upon contact with the target or by the tracer relay igniting charge (if this feature is incorpo-rated). A summary of 40mm ammunition charac-teristics is presented in Table A-1.

A-3.1.5. Projectiles. The 40mm projectiles include a number of basic projectile types as listed in Table A-1. Some projectile types are inert while others are high explosive and incendiary loaded; they may or may not contain tracers. The high-explosive charge, when used, is trinitrotoluene (TNT) and all projectiles having an explosive charge are fuzed with a point detonating fuze that has an out-of-line explosive train of the centrifugal, rotor-arming type (see Chapter 4, Paragraph 4-8.2).

A-3.1.5.1. Armor Piercing (AP). The AP pro-jectile consists of a hardened steel monobloc slug, crimp-fitted on the blunt ogival nose with a thin steel, streamlined, windshield cap to reduce aero-dynamic drag. A rotating band encircles the pro-jectile near the base. The AP projectile is the same as the AP-T except the tracer cavity is plugged.

A-3.1.5.2. Armor Piercing, Tracer (AP-T). The AP-T projectile (Figure 3-13) consists of a hardened steel monobloc slug, crimp-fitted on the blunt ogival nose with a thin steel, streamlined, windshield cap to reduce aerodynamic drag. A tracer element in the base of the projectile provides a visible trace for approximately 12 seconds. A rotating band encircles the projectile near the base.

A-3.1.5.3. High Explosive, Plugged, Dummy Nose Fuze (HE-P-NP). The HE-P-NP projectile (Figure A-13) is a thin-walled projectile. It is filled with an explosive (TNT) charge that bursts on impact and has no tracer or self-destructive feature. The projectile nose and base are threaded. The nose is fitted with a dummy fuze, and a plug is installed in the base.

High explosive incendiary tracer, self-destruct

HEIT-SD B559

High explosive incendiary tracer, dark ignition, self-destruct

HEIT-DI-SD B560

High explosive plugged, dummy nose plug

HE-P-NP B561

High explosive tracer, self-destruct

HET-SD B562

Blind loaded and plugged

BL-P B563

Blind loaded and tracer

BL-T B564

Dummy -- B565

MOUNT TYPE GUN

MK 1/all MODs

twin MK 1 and MK 2

MK 2/all MODs

quad MK 1 and MK 2

MK 3/all MODs

single MK 5


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Table A-1 40 Millimeter Ammunition Data

Projectile Propelling Charge TotalWeight

(kg)Cartridge Assembly DODIC Body Explosive

Filter Tracer Fuze Cartridge Case Primer Propellant Wt.

(g. Nominal)

AP B551 M81A1 None None None MK 2 Brass MK 3 Steel

MK 22 Perc M1 326.6 2.077

AP-T B552 M81A1 None Integral None MK 2 Brass MK 3 Steel

MK 22 Perc M1 326.6 2.077

HEI-P-NP B556 MK 2 TNT and Incendiary

81.65 g

Plugged Dummy MK 2 Brass MK 3 Steel

MK 22 Perc M1 326.6 2.155

HEI-SD B557 MK 2 TNT and Incendiary

81.65 g

MK 11 Tracer

MK 27 MK 2 Brass MK 3 Steel

MK 22 Perc M1 326.6 2.155

HEIT-NSD B558 MK 2 TNT and Incendiary

81.65 g

MK 14 Tracer


MK 22 Perc M1 326.6 2.155

HEIT-SD B559 MK 2 TNT and Incendiary

81.65 g

MK 11 Tracer


MK 22 Perc M1 326.6 2.155

HEIT-DI-SD B560 MK 2 TNT and Incendiary

81.65 g

MK 11 Tracer


MK 22 Perc M1 326.6 2.155

HE-P-NP B561 MK 2 TNT 81.65 g MK 11 Tracer

Dummy MK 2 Brass MK 3 Steel

MK 22 Perc M1 326.6 2.155

HET-SD B562 MK 2 TNT MK 11 MK 27 MK 2 Brass MK 22 Perc M1 326.6 2.155

81.65 g Tracer MK 3 Steel

BL-P B563 MK 2 None Plugged None MK 2 Brass MK 3 Steel

MK 22 Perc M1 326.6 2.155

BL-T B564 MK 2 None MK 11 Tracer

None MK 2 Brass MK 3 Steel

MK 22 Perc M1 326.6 2.155

Dummy B565 MK 2 None None Dummy MK 1 Brass None None 2.155

Figure A-13 40 Millimeter High Explosive, Plugged Projectile

Figure A-14 40 Millimeter High Explosive, Incendiary, Plugged Projectile

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A-3.1.5.4. High Explosive Incendiary, Plugged, Dummy Nose Fuze (HEI-P-NP). The HEI-P projectile (Figure A-14) is a thin-walled projectile, filled with a combination of high explosive (TNT) and an incendiary mix. The projectile consists of a hollow metal body that is internally threaded at both ends. The high explosive and incendiary compound are fitted into the same cavity of the projectile, with the incendiary compound being located in the center. The incendiary feature does not reduce blast or fragmentation and is particularly effective against fuel targets. The nose of the projectile is fitted with a dummy fuze (MK 27), and a plug is installed in the base.

A-3.1.5.5. High Explosive Incendiary, Self-Destruct (HEI-SD). The HEI-SD projectile (Fig-ure A-15) is a thin-walled projectile, filled with a combination of high explosive (TNT) and an incendiary compound. The high explosive and incendiary compound are fitted into the same cav-ity of the projectile, with the incendiary compound being located in the center of the explosive charge. The incendiary feature does not reduce the blast or fragmentation and is particularly effective against fuel targets. The projectile nose and base are threaded. The nose is fitted with a point detonating (PD) fuze (MK 27); the base is assembled with a non-luminous self-destructive tracer (MK 11), which protrudes approximately 0.60 inch from the base and burns for 8 to 10 seconds (equivalent to a range of 3,800 to 4,300 yards). As the tracer burns out, the relay igniting charge is ignited and deto-nates the bursting charge of the projectile unless prior detonation has been caused by fuze impact.

A-3.1.5.6. High Explosive Incendiary Tracer, Non-Self-Destruct (HEIT-NSD). The HEIT-NSD projectile (Figure A-16) is a thin-walled projectile, filled with a combination of high explosive (TNT) and an incendiary compound. The high explosive and incendiary compound are fitted into the same cavity of the projectile, with the incendiary com-pound being located in the center of the explosive charge. The incendiary feature does not reduce blast or fragmentation and is particularly effective against fuel targets. The projectile nose and base are threaded. The nose is fitted with a PD fuze (MK 27), and the base is assembled with a tracer (MK 14) with the self-destruct feature omitted. The tracer contains an igniting charge and a red tracer composition. The relay housing cavity is blocked to eliminate the self-destructive feature. The tracer protrudes approximately 0.60 inch from the base and burns for 8 to 10 seconds, which is equivalent to a range of 3,800 to 4,300 yards.

A-3.1.5.7. High Explosive Incendiary Tracer, Self-Destruct (HEIT-SD). The HEIT-SD projec-tile (Figure A-17) is a thin-walled projectile, filled with a combination of high explosive (TNT) and an incendiary compound. The high explosive and incendiary compound are fitted into the same cav-ity of the projectile, with the incendiary compound being located in the center of the explosive charge. The incendiary feature does not reduce blast or fragmentation and is particularly effective against fuel targets. The projectile nose and base are threaded internally. The nose is fitted with a PD fuze (MK 27); the base of the projectile is fitted with a self-destruct tracer (MK 11), which extends approximately 0.60 inch beyond the base. The tracer contains an igniting charge, red tracer com-

Figure A-15 40 Millimeter High Explosive, Incendiary, Self-Destruct Projectile

Figure A-16 40 Millimeter High Explosive, Incendiary, Tracer, Non-Self-Destruct Projectile

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position, and a relay igniting charge of black pow-der. The tracer burns for 8 to 10 seconds, which is equivalent to a range of 3,800 to 4,300 yards. As the tracer burns out, the relay igniting charge is ignited and detonates the projectile unless prior detonation has been caused by fuze impact.

A-3.1.5.8. High Explosive Incendiary Tracer, Dark Ignition, Self-Destruct (HEIT-DI-SD). The HEIT-DI-SD projectile (Figure A-18) is a thin-walled projectile, filled with a combination of high explosive (TNT) and an incendiary compound. The high explosive and incendiary compound are fitted into the same cavity of the projectile, with the incendiary compound being located in the center of the explosive charge. The incendiary feature does not reduce blast or fragmentation and is particularly effective against fuel targets. The projectile nose is fitted with a PD fuze (MK 27); a dark-ignition, self-destruct tracer (MK 11), which does not light until the projectile is approximately 300 yards from the gun muzzle, is installed in the boattailed base. This cartridge self-destructs at approximately 4,600 yards, unless prior detonation has been caused by functioning of the fuze. The tracer is dim and is not as visible as regular tracers. The tracer protrudes approximately 0.60 inch from the base and burns for 8 to 10 seconds.

A-3.1.5.9. High Explosive Tracer, Self-Destruct (HET-SD). The HET-SD projectile (Figure A-19) is a thin walled projectile. It contains a TNT bursting charge, a PD fuze (MK 27), and a self-destruct tracer (MK 11). The projectile nose and base are internally threaded to receive the fuze tracer assembly. The tracer assembly, which protrudes approximately 0.60

inch from the base, contains an igniting charge, a red tracer composition, and a relay igniting charge of black powder. The tracer composition burns with a visible trace for 8 to 10 seconds, which is equivalent to a range of 3,800 to 4,300 yards. As the tracer burns out, the relay igniting charge ignites and detonates the bursting charge of the shell unless prior detonation has been caused by fuze impact.

A-3.1.5.10. Blind Loaded and Plugged/Blind Loaded and Tracer (BL-P/BL-T). Blind loaded cartridges or AP cartridges that have no high explosive load should be loaded as the first two cartridges in the feeder magazine or clips that are to be fired first. This practice allows firing through the thin fabric or rubber muzzle covers used to pro-tect the gun barrels from the weather. It also pre-

Figure A-17 40 Millimeter High Explosive, Incendiary Tracer, Self-Destruct Projectile

Figure A-18 40 Millimeter High Explosive Incendiary Tracer, Dark Ignition, Self-Destruct

Projectile

Figure A-19 40 Millimeter High Explosive Tracer, Self-Destruct Projectile

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vents premature initiation of a live-loaded projectile fuze by ice or water in the gun barrel when the gun must be quickly put in action. Under no circumstances should a projectile with a PD fuze be fired through any muzzle cover. The stan-dard (MK 2) thin-walled projectile body is filled with inert material to bring the cartridges within the weight tolerance of the service projectile. The nose of both projectiles is fitted with an inert fuze (MK 27). The boattail of the BL-P cartridge is plugged flush with the base of the projectile. The BL-T cartridge has a standard red tracer assembled in the projectile boattail. These cartridges are for target practice, ranging, and proving ground tests.

A-3.1.5.11. Dummy. The dummy cartridge con-sists of a modified service projectile and a modi-fied cartridge case. The projectile is inert and is fitted with a dummy nose fuze. The cartridge case has a base plug in place of a primer, and a copper rivet is centered in the base plug to avoid damage to the firing pin of the weapon. The projectile and case are held together by a steel retaining rod extending through the case. One end of the rod is threaded into the tracer cavity in the dummy pro-jectile. The other end has an internally threaded socket to fit the base plug of the cartridge case.

A-3.1.6. Propelling Charge. The propelling charges (Figure A-20) for 40mm ammunition are assembled in either MK 2 brass or MK 3 steel car-tridge cases. The cartridge case is attached rigidly to the projectile by means of a 360-degree crimp. The propelling charge consists of a percussion primer (MK 22), 326.6 grams of M1 propellant, and 5 grams of lead foil.

A-3.1.7. Packing. The ammunition is handled and shipped according to OP 4 and OP 5. The ammunition and container are painted, marked, and lettered according to WS 18782. The following bulk packaging requirements apply:

A-3.1.8. Ballistic Data. The ballistic data for the 40 millimeter cartridges are as follows:

A-3.1.9. Average Muzzle Velocity.AP projectile – 2,870 feet per secondHE projectile – 2,870 feet per secondHEI projectile – 2,890 feet per secondBL projectile – 2,870 feet per second.

A-3.1.10. Maximum Range.AP projectile – 9,600 yardsHE projectile – 10,800 yards

Figure A-20 40 Millimeter Propelling Charge Assembly

NALC TYPE PALLETIZING PACKING

B551 AP MIL-STD-1323/10 DWG 423999

B552 AP-T MIL-STD-1323/10 DWG 423999

B556 HEI-P-NP MIL-STD-1323/10 DWG 423999

B557 HEI-SD MIL-STD-1323/10 DWG 423999

B558 HEIT-NSD MIL-STD-1323/10 DWG 423999

B559 HEIT-SD MIL-STD-1323/10 DWG 423999

B560 HEIT-DI-SD MIL-STD-1323/10 DWG 423999

B561 HEP-NP MIL-STD-1323/10 DWG 423999

B562 HET-SD MIL-STD-1323/10 DWG 423999

B563 BL-P MIL-STD-1323/10 DWG 423999

B564 BL-T MIL-STD-1323/10 DWG 423999

B565 Dummy MIL-STD-1323/10 DWG 423999

SW030-AA-MMO-010

A-12

HEI projectile – 10,800 yardsBL projectile – 10,800 yards

A-3.2. 3-Inch 50-Caliber Ammunition. The 3-inch, 50 caliber ammunition is in the

fixed round family of ammunition. The ammuni-tion is mechanically hoisted, manually transferred from hoist to the loader, and then mechanically loaded in the gun mount. This system was primar-ily developed for antiair craft defense, but because of the small caliber and relatively short range capa-bility of this gun system, the role of ships carrying this gun system has been reassigned to self-protec-tion, counter-battery, and harassment/suppression. Because of the gun mount's wide arc and elevation capability, this system is effective against surface targets. The ammunition is identified and issued as follows:


High explosive, variable time, self-destructive, flashless, rapid fire

HE-VT-SD-RF C136

High explosive, variable time, non-self-destructive, flashless, rapid fire

HE-VT-NSD-RF C137

High explosive, variable time, self-destructive, nonflashless, rapid fire

HE-VT-SD-RF C140

High explosive, variable time, non-self-destructive, nonflashless, rapid fire

HE-VT-NSD-RF C141

High explosive, variable time, non-self-destructive, with point detonating feature, flashless propellant, rapid fire (with or without fuze cavity liner)

HE-VT-NSD-RF C150

High explosive, variable time, non-self-destructive, with point detonating feature, nonflashless propellant, rapid fire (with or without cavity liner)

HE-VT-NSD-RF C151

High explosive, variable time, self-destructive, with point detonating feature, flashless propellant, rapid fire (with or without cavity liner)

HE-VT-SD-RF C152

High explosive, variable time, self-destructive with point detonating feature, nonflashless propellant, rapid fire (with or without cavity liner)

HE-VT-SD-RF C153

High explosive, variable time, self-destructive, nonflashless, slow fire

HE-VT-SD-SF C207

High explosive, variable time, non-self-destructive, nonflashless, slow fire

HE-VT-NSD-SF C208

High explosive, variable time, self-desctructive, flashless, slow fire (with or without cavity liner)

HE-VT-SD-SF C355

High explosive, variable time, non-self-destructive, flashless, slow fire

HE-VT-NSD-SF C356

High explosive, passive infrared, nonflashless, rapid fire (with or without cavity liner)

HE-IR-RF C306

High explosive, passive infrared, flashless, rapid fire (with or without cavity liner)

HE-IR-RF C307

High explosive, passive infrared, nonflashless, slow fire

HE-IR-SF C321

High explosive, passive infrared, flashless, slow fire

HE-IR-SF C322

High explosive, point detonating, nonflashless, slow fire

HE-PD-SF C349

High capacity (HE), nonflashless, slow fire

HC-SF C218

High capacity (HE), flashless, slow fire

HC-SF C296


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A-13

A-3.3. 5-Inch, 38-Caliber Ammunition.The 5-inch, 38 caliber ammunition is the

smallest caliber of in-service Navy ammunition in the separated ammunition category. Separated ammunition is defined by the physical characteris-tic of the projectile and the propelling charge not being attached to each other in any way but loaded into the gun chamber in a single operation (i.e., one-ram cycle). A complete round of ammunition consists of a projectile and a propelling charge, which is packed, shipped, and issued separately. The 5-inch, 38 caliber system was developed with a capability to engage sea, air, or land targets under local or remote control. The 5-inch, 38 caliber gun has the added capability of firing a rocket assisted projectile for use at extended ranges.

High capacity (HE), point detonating, flashless, rapid fire

HC-RF C347

High capacity (HE), point detonating, nonflashless, rapid fire

HC-RF C348

Antiaircraft (HE), non-flashless, slow fire

AA-SF C299

Antiaircraft (HE), flash-less, slow fire

AA-SF C302

Armor piercing, flashless, rapid fire

AP-RF C143

Armor piercing, non-flashless, slow fire

AP-SF C212

Armor piercing, flash-less, slow fire

AP-SF C215

Illuminating, rapid fire ILLUM-RF C172

Illuminating, slow fire ILLUM-SF C305

Target practice, nonfragmenting, variable time, self-destructive, nonflashless, rapid fire

TP-VT-SD-RF C162

Target practice, nonfragmenting, variable time, non-self-destructive, nonflashless, rapid fire

TP-VT-NSD-RF C164

Target practice, nonfragmenting, variable time, self-destructive, nonflashless, slow fire

TP-VT-SD-SF C319

Target practice, nonfragmenting, variable time, non-self-destructive, nonflashless, slow fire

TP-VT-NSD-SF C320

Target practice, nonfragmenting, variable time, self-destructive, (with modified booster), nonflashless, rapid fire

TP-VT-SD-RF C373

Target practice, nonfragmenting, variable time, non-self-destructive, (with modified booster), non-flashless, rapid fire

TP-VT-NSD-RF C375


Blind loaded, dummy nose plug, plugged, nonflashless, rapid fire

BL-P-RF C178

Blind loaded, dummy nose plug, plugged, flashless, rapid fire

BL-P-RF C179

Blind loaded and plugged, nonflashless, slow fire

BL-P-SF C338

Blind loaded and plugged, flashless, slow fire

BL-P-SF C341

Short, clearing charge, percussion primer, slow fire

C184

Short, clearing charge, electric primer, rapid fire

C185

Blank saluting charge, 1-pound black powder, slow fire

C139

Blank saluting charge, 2-pound black powder, slow fire

C183

Dummy cartridge, all loading machine

C182

Dummy cartridge, slow fire mount drill

C370

Dummy cartridge, rapid fire mount loader cycling

C371/C372


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A-14

A-3.3.1. Projectile Inventory. The basic con-figurations of projectiles in the 5-inch, 38 caliber ammunition inventory are as follows:

A-3.3.2. Propelling Charge Inventory. The basic configurations of 5-inch, 38 caliber propel-ling charges in the inventory are as follows:

A-3.3.3. Ammunition/Interface. The 5-inch 38 caliber ammunition is used in the following gun mounts:

This system can be fired at a rate of 15 rounds per minute per barrel.

A-3.3.4. Ammunition Characteristics. The 5-inch, 38 caliber ammunition contains great versa-tility and many projectile and fuze combinations as shown in Table A-2.


High explosive, con-trolled variable time

HE-CVT D225/D289

High explosive, mechan-ical time

HE-MT D241/D243

High explosive, mechan-ical time/point detonat-ing

HE-MT/PD D292


HE-PD D238/D245

High explosive, infrared HE-IR D280High explosive, variable time

HE-VT D226/D228/D232/D233

High capacity, dummy nose plug/point detonat-ing

HC D235/D242

Antiaircraft (high explo-sive) mechanical time

AAC D217/D230

Rocket assisted (high explosive) controlled variable time

RAP D260/D261/D262

Common, base detonat-ing spotting dye

COM D237

Illuminating, mechanical time

ILLUM D244/D255

Illuminating, mechanical time/point detonating

ILLUM D256

White phosphorus (smoke), mechanical time

WP-MT D247/D281

White phosphorus (smoke), point detonat-ing

WP-PD D246

Target practice (puff), point detonating

TP-Puff-PD D220

Target practice (puff), mechanical time

TP-Puff-MT D221

Target practice-nonfrag-menting, variable time

VT NON-FRAG D248/D250/D251

Chaff dispensing, mechanical time

Chaff D286/D287

Blind loaded and plugged/tracer

BL-P/T D267

Dummy – D252/D263

Propelling Charge DODIC

Full charge, universal, cork or foam plug D264Full charge, nonflashless, cork or foam plug D272Full charge, flashless. cork or foam plug D274Reduced charge, nonflashless, cork plug D282Clearing charge, flashless, cork or foam plug D227/

D296/D306

Mount Type Gun

MK 24 Single (open) MK 12MK 28 Twin (enclosed) MK

12(2)MK 30 Single-light (open) MK 12MK 30 Single-heavy (enclosed) MK 12MK 32 Twin (enclosed) MK

12(2)MK 37 Single (open) MK 12MK 38 Twin (enclosed) MK

12(2)


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A-15

Table A-2 5-Inch, 38-Caliber Projectile Data

Projectile Fuze Total Weight

(lb.)(Approx.)

DODICType Assembly Body Explosive

Filler Nose AD Base

HE-CVT MK 56 A-3 M514A1 MK 52 Plug 53.3 D225

MK 66 A-3 M514A1 MK 52 Solid 53.3 D225

MK 35 A-3 M514A1 MK 52 Plug 53.3 D289

MK 47 A-3 M514A1 MK 52 Plug 53.3 D289

MK 49 A-3 M514A1 MK 52 Plug 53.3 D289

MK 51 A-3 M514A1 MK 52 Solid 53.3 D289

HE-MT MK 35 A-3 MK 50 MK 52 Plug 54.7 D241

MK 47 A-3 MK 50 MK 52 Plug 54.7 D241

MK 49 A-3 MK 50 MK 52 Plug 54.7 D241

MK 51 A-3 MK 349 MK 54 or 379 Solid 54.7 D243

MK 66 A-3 MK 349 MK 379 Solid 54.7 D243

HE-MT/PD MK 99/4 MK 51 A-3 MK 403 MK 379 Solid 54.7 D292

HE-PD MK 35 A-3 or Expl-D MK 29 MK 43, 52, 54, or 379 Plug 54.0 D238

MK 47 A-3 or Expl-D MK 29 MK 43, 52, 54, or 379 Plug 54.0 D238


MK 51 A-3 or Expl-D MK 29 MK 52, 54, or 379 Solid 54.0 D245


MK 66 A-3 or Expl-D MK 29 MK 52, 54, or 379 Solid 54.0 D245

MK 120/0 MK 51 A-3 MK 29/5, 29/3 RFM

MK 379 Solid 54.0 D245

HE-IR MK 35 A-3 MK 90 MK 39 Booster Plug 55.4 D280

MK 47 A-3 MK 90 MK 39 Booster Plug 55.4 D280

MK 49 A-3 MK 90 MK 39 Booster Plug 55.4 D280

MK 51 A-3 MK 90 MK 39 Booster Solid 55.4 D280

MK 119/0 MK 51 A-3 MK 90/1 MK 30 Booster Solid 55.4 D280

HE-VT-SD MK 35 A-3 MK 71/12 MK 30 Booster Plug 55.1 D226

MK 47 A-3 MK 71/12 MK 30 Booster Plug 55.1 D226



HE-VT-NSD MK 35 A-3 MK 71/11 MK 30 Booster Plug 55.1 D228




HE-VT-SD MK 35 A-3 MK 71/6, 8, or 10 MK 44 Plug 55.1 D232

MK 47 A-3 MK 71/6, 8, or 10 MK 44 Plug 55.1 D232

MK 49 A-3 MK 71/6, 8, or 10 MK 44 Plug 55.1 D232

SW030-AA-MMO-010

A-16

HE-VT-NSD MK 35 A-3 MK 71/5, 7, or 9 MK 44 Plug 55.1 D233

MK 47 A-3 MK 71/5, 7, or 9 MK 44 Plug 55.1 D233

MK 49 A-3 MK 71/5, 7, or 9 MK 44 Plug 55.1 D233

HC MK 35 A-3 or Expl-D MK 29 MK 44, 52, or 54 MK 28, 31 53.3 D235

MK 49 A-3 or Expl-D MK 29 MK 44, 52, or 54 MK 28, 31 53.3 D235

MK 52 A-3 or Expl-D MK 29 MK 44, 52, or 54 MK 83 53.3 D235

MK 52 A-3 or Expl-D Plug MK 52 MK 83 53.3 D242

AAC MK 52 A-3 or Expl-D MK 61/1 MK 44 MK 83 55.1 D217

MK 52 A-3 or Expl-D MK 61/1 MK 52 MK 83 55.1 D217

MK 52 A-3 or Expl-D MK 61/1 MK 54 MK 83 55.1 D217

MK 35 A-3 or Expl-D MK 50 MK 44 MK 28 55.1 D230



MK 56 A-3 or Expl-D MK 349 MK 379 - 55.1 D230

MK 57/0 A-3 M514A1 MK 52 - 55.0 D260

MK 57/1 A-3 M514A1 MK 52 - 55.0 D261

MK 57/2 A-3 MK 357 - - 55.0 D262

MK 57/2 A-3 MK 358 - - 55.0 D262

MK 57/2 A-3 MK 359 - - 55.0 D262

COM MK 32 Expl-D - - MK 20 55.0 D237

MK 38 Expl-D - - MK 20 55.0 D237

MK 46 Expl-D - - MK 20 55.0 D237

ILLUM MK 87/2 MK 50 MK 11 MK 61/1 MK 384 - 54.3 D244

- MK 30 MK 4 or 11 MK 61 - - 54.3 D244

- MK 44 MK 4 or 11 - - - 54.3 D244

- MK 50 MK 4 or 11 MK 61 - - 54.3 D244

MK 87/0 MK 50 MK 11 MK 349/0,1 MK 384 - 54.3 D255

- MK 30 MK 4 or 11 MK 50 or 349 - - 54.3 D255

- MK 44 MK 4 or 11 MK 50 or 349 - - 54.3 D255

- MK 50 MK 4 or 11 MK 50 or 349 - - 54.3 D255

MK 87/3 MK 50 MK 11 MK 403 MK 384MK 413

- 54.3 D256

Table A-2 5-Inch, 38-Caliber Projectile Data (Continued)


(lb.)(Approx.)


Filler Nose AD Base

SW030-AA-MMO-010

A-17

WP MK 73/0 MK 50 M5 Canister MK 66/0 - - 54.5 D246

- MK 30 M5 Canister MK 29/3 or 66 - - 54.5 D246



MK 73/1 MK 50 M5 Canister MK 29/3 MK 384 - 54.5 D246

MK 74/1 MK 50 M5 Canister MK 349 MK 384 - 54.5 D247

- MK 30 M5 Canister MK 50 or 349 - - 54.5 D247



- MK 50 M5 Canister MK 61 - - 54.5 D281

- MK 50 M5 Canister MK 403/0 MK 384 - 54.5 D298

TP-PUFF - MK 52 Reactant unit MK 29/3,5 MK 54/2 - 54.5 D220

MK 126 MK 52 Reactant unit MK 29/3,5 MK 54/2 - 54.5 D220

- MK 52 Reactant unit MK 349/0 MK 54/2 - 54.5 D221

MK 103/0 MK 52 Reactant unit MK 349/0 MK 379/0 - 54.5 D221



VT-NON-FRAG-SD

MK 95/0 MK 51 MK 2 MK 71/12 MK 30 bstr Solid 54.6 D248

- MK 35 MK 2 MK 71/12 MK 30 bstr Plug 54.6 D248



- MK 31 MK 2,3, or 3/1 MK 71/6,8,10 MK 44 Plug 54.6 D249



- MK 51 MK 2,3, or 3/1 MK 71/6,8,10 MK 44 Solid 54.6 D249

VT-NON-FRAG-NSD






- MK 31 MK 2,3,or 3/1 MK 71/5,7,9 MK 44 Plug 54.5 D251


- MK 2,3,or 3/1 MK 71/5,7,9 MK 44 Plug 54.6 D251





(lb.)(Approx.)


Filler Nose AD Base

SW030-AA-MMO-010

A-18

A-3.3.5. Projectiles. The projectiles used in the 5-inch, 38 caliber ammunition are described in the following subordinate paragraphs.

A-3.3.5.1. High Explosive (HE). These general purpose projectiles (Figure A-21) are used primar-ily to provide blast and fragmentation. The projec-tile can be fuzed with either an impact, a time, or a proximity fuze. The proximity fuzed projectiles are fitted with fuze liners to permit interchanging nose fuzes without remote equipment (ashore only). In all cases where proximity fuzing is used, no fuze is used in the base. In addition, those assemblies designated below as HE-CVT, HE-MT, HE-PD, HE-MT/PD, HE-IR, and HE-VT do not have base fuzes. The weights of the projectiles vary slightly depending upon explosive/fuze com-binations used. The bodies for each of these pro-jectiles are essentially the same except for the base. The MK 35, MK 47, and MK 49 have a 1.5-inch base fuze hole, whereas the MK 52 and MK 56 have a 2.0-inch base fuze hole. The MK 51 and

MK 66 projectiles have a solid base. The bodies for the MK 56 and MK 66 are made of a high-frag-mentation steel, whereas the other projectile bodies are made from a ductile steel with low-fragmenta-tion characteristics. The principal variations in these projectiles are described below.

Chaff MK 78/0 MK 50 MK 21 MK 349 MK 384 - 54.6 D286

- MK 44 Type A MK 61 - - 54.6 D286

- MK 50 Type A MK 61 - - 54.6 D286

- MK 50 MK 15 MK 50 or 349 - - 54.6 D287

- MK 50 MK 15 MK 50 or 349 - - 54.6 D287

BL-PT - MK 31 Inert Dummy - Plug 54.6 D267

- MK 34 Inert Dummy - Plug 54.6 D267

MK 110/0 MK 35 Inert Dummy - Plug 54.6 D267



MK 110/3 MK 51 Inert Dummy - Solid 54.6 D267



Dummy MK 1 - - - - - - D252

MK 4 - - - - - - D252

MK 2 - - - - - - D263



(lb.)(Approx.)


Filler Nose AD Base

Figure A-21 5-Inch, 38-Caliber High Explosive Projectile

SW030-AA-MMO-010

A-19

A-3.3.5.1.1. High Explosive, Controlled Vari-able Time (HE-CVT). This projectile is avail-able with either a high-fragmentation steel (obso-lescent) (D225) or a conventional low-fragmentation steel (D289) body. The high-frag-mentation body projectile was designed primarily for use against personnel and light surface targets. The HE-CVT can be used in the antiaircraft role in an emergency; however, the reliability is lower than variable time or infrared fuzed projectiles in this mode. The nose of the projectile body is threaded internally and fitted with a CVT-RF, prox-imity, and AD fuze. The fuze is separated from the Composition A-3 explosive load by a cavity liner to permit fuze replacement without remote equip-ment. The base of the projectile is either plugged or solid.

A-3.3.5.1.2. High Explosive, Mechanical Time (HE-MT). This low-fragmentation steel body pro-jectile is designed primarily for use against air-borne targets and secondly against surface targets that are vulnerable to airburst. The nose of the pro-jectile body is threaded internally and fitted with an MT and AD fuze. This projectile is available with (D241) or with/without (D243) a cavity liner to separate the fuze from the Composition A-3 explo-sive load. The base of the projectile is either plugged or solid.

A-3.3.5.1.3. High Explosive, Point Detonating (HE-PD). This low-fragmentation steel body, Composition A-3 explosive-loaded projectile is designed for use against surface targets vulnerable to an impact burst. The nose of the projectile body is threaded internally for an auxiliary detonating fuze adapter that is fitted with a PD and AD fuze, with or without a cavity liner. The base of the pro-jectile is either plugged or solid.

A-3.3.5.1.4. High Explosive, Mechanical Time/Point Detonating (HE-MT/PD). This projectile is similar to the HE-MT projectile except that the nose time fuze has a point detonating backup that causes a self-destructive action on surface impact in case of airburst function failure, due to clock failure or surface impact before expiration of the set time. An AD fuze is not to be employed when the projectile body is configured for short-intrusion fuzes.

A-3.3.5.1.5. High Explosive, Point Detonating/Delay (HE-PD/D). This projectile is similar to the HE-PD projectile except that it is configured for direct fit (without an adapter) of short-intrusion fuzes. The HE-PD/D permits selection of super-quick action on surface impact or delay after impact to allow target penetration before detona-tion.

A-3.3.5.1.6. High Explosive, Infrared (HE-IR) . This low-fragmentation steel body, Composition A-3 explosive-loaded projectile is designed exclu-sively for use against infrared targets (i.e., jet air-craft and missiles). The nose of the projectile body is threaded internally and fitted with a VT-IR prox-imity fuze that has an integral AD fuze. A point detonating feature is also incorporated into the nose fuze in the event the target is missed. The fuze is separated from the Composition A-3 explo-sive load by a cavity liner to permit fuze replace-ment without remote equipment. The base of the projectile is either plugged or solid.

A-3.3.5.1.7. High Explosive, Variable Time (HE-VT). This low-fragmentation steel body pro-jectile is designed for use against targets that are vulnerable to airburst. The nose of the projectile body is threaded internally and fitted with a VT-RF proximity fuze, supplemented by either a booster or an AD fuze. A self-destruct capability is incor-porated into the nose fuze of D226 and D232 pro-jectiles, but is omitted in D228 and D233 projectiles. The nose fuze is separated from the Composition A-3 explosive load by a cavity liner to permit fuze replacement without remote equip-ment. The base of the projectile is either plugged or solid.

A-3.3.5.2. High Capacity (HC). These low-fragmentation, thin-walled, steel body projectiles (Figure A-22) are designed for use against unar-mored surface targets or shore installations that are vulnerable to impact burst. The projectile nose and base are threaded internally to receive nose and base fuzing. The projectile cavity is filled with either Explosive D or Composition A-3. HC pro-jectiles are issued with either a dummy nose plug (D242) or with a point detonating fuze (D235) installed. A PD or MT nose fuze may be installed in the D242 projectile prior to use if the approved

SW030-AA-MMO-010

A-20

equipment is used by an authorized shore facility. All HC projectiles are issued with AD and base fuzes installed and normally with a PD fuze.

A-3.3.5.3. Antiaircraft Common (AAC). This low-fragmentation steel body projectile (Figure A-23) is designed for use against airborne or surface targets that are vulnerable to airburst. The projec-tile body nose and base are threaded internally and fitted with nose and base fuzing to provide increased detonating reliability. The nose is fitted with a fuze adapter to receive an MT and AD fuze. The projectile cavity is filled with either Explosive D or Composition A-3.

A-3.3.5.4. Rocket Assisted Projectile (RAP).

DURING HANDLING OF A RAP, A DROP IN EXCESS OF 24 INCHES ON THE BASE OF THE PROJEC-TILE IN WHICH A DECK PIN (RIVETHEAD), BOLT, OR MIS-CELLANEOUS OBJECT STRIKES THE CENTER HOLE OF THE IGNITER, SUFFICIENT STRIK-ING ENERGY COULD BE PRO-VIDED TO ACTUATE THE IGNITER. IN THIS EVENT, IGNI-TION OF THE ROCKET MOTOR MAY BE DELAYED 20 TO 30 SEC-ONDS. ALL PERSONNEL SHOULD IMMEDIATELY EVAC-UATE THE AREA. DO NOT ATTEMPT DISPOSAL PRIOR TO ROCKET MOTOR IGNITION. IF THE ROCKET MOTOR BURNS IN A CLOSED COMPARTMENT, ENSURE THAT THE AREA IS CLEAR OF FUMES PRIOR TO RE-ENTRY. DISPOSE OF THE PROJECTILE IN ACCORDANCE WITH STANDARD EXPLOSIVE ORDNANCE DISPOSAL PRAC-TICE.

The projectile (Figure A-24) is made up of a solid propellant rocket motor (MK 62) with a delay ignition element and a controlled variable-time fuzed warhead (MK 74), designed for use against personnel and light material targets. The rocket motor is ignited when the gas pressure generated by the propelling charge propellant flexes a bel-leville spring that strikes a percussion primer assembly, initiating the pyrotechnic delay column. After a 23-second delay, the delay column burns the ignition charge, which ignites the propellant grain in the rocket motor. When the motor is ignited, the igniter, which is sealed into the motor case base with a gas check gasket, is blown out. The RAP can be handled, stowed, and fired almost identically to the conventional 5-inch projectiles now in use and is propelled by the same charge.

Figure A-22 5-Inch, 38-Caliber High Capacity Projectile

Figure A-23 5-Inch, 38-Caliber Antiaircraft Common Projectile

SW030-AA-MMO-010

A-21

The 5-inch, 38 caliber MK 57 RAP has the same shape as the standard MK 49 projectile except that the length has been increased 2-1/8 inches and the base has been boattailed to provide additional range. To ensure ignition reliability, the 5-inch, 38 caliber RAP must be fired with a propelling charge having a 1-inch-diameter by 2-5/8-inch-deep hole centered in the front face of the closure plug. Pro-pelling charges equipped with either cork or plastic plugs with holes will normally be supplied by a depot. This special purpose Navy gun-type ammu-nition is used with manual inputs to existing gun fire control systems (GFCS) and a 5-inch, 38 cali-ber ballistic slide rule covered by ORDALT No. 6970 in initial firing ships. The 5-inch, 38 caliber automatic inputs to GFCS in the final installations are covered by ORDALT No. 6971.

NOTEThe 2-1/8-inch increased length of the 5-inch, 38 caliber RAP presents an interface problem with gun mount hoist operations. This problem is covered by modifications described in ORDALT No. 6827 for 5-inch, 38 caliber gun projectile hoists MK 2 and MK 4. Special reversible battens are also required in shipboard magazines to accept the 5-inch, 38 caliber RAP.

A-3.3.5.5. Common (COM). The COM projec-tile (Figure A-25) is designed to penetrate approxi-mately one-third of its caliber of armor. This projectile has both a base plug and a base detonat-ing fuze. Once inside the target, the delayed action

base fuze functions to detonate the explosive filler. Prior to modern GFCS technology, various colored spotting dyes were used to identify firing accuracy. Dyes are no longer required and issues may or may not have dyes included. The projectile, which is made of forged steel, is loaded with 2.04 pounds of Explosive D.

A-3.3.5.6. Illuminating (ILLUM). The ILLUM projectile (Figure A-26) is designed to deploy a parachute suspended pyrotechnic candle for target illumination. The projectile illuminating load and a small black-powder explosive charge are sealed within the mechanical time fuzed projectile by a base plate. When the fuze functions, it ignites the black powder, which expels the projectile’s illumi-nating load. The illuminating composition is a powdered magnesium mixed with an oxidizer that burns for approximately 50 seconds with a candle power of 600,000 lumens.

Figure A-24 5-Inch, 38-Caliber Rocket Assisted Projectile

Figure A-25 5-Inch, 38-Caliber Common Projectile

Figure A-26 5-Inch, 38-Caliber Illuminating Projectile

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A-22

A-3.3.5.7. White Phosphorus (WP) (Smoke). The intended use of the WP projectile (Figure A-27) is to provide spotting, antipersonnel screening, and limited incendiary effects. It may be used with a PD fuze (D246), a MT fuze (D247 or D281), or a combination (D298). When the fuze functions, it sets off the expelling charge, which ignites the delay element and forces the canister (M5) from the rest of the projectile. The burster tube of the canister detonates and disperses a cloud of white phosphorus approximately 50 yards in diameter and lasting 7 minutes in still air. The tendency of white phosphorus to break into very small pieces that burn rapidly, together with its low melting point that sometimes causes melting in storage, led to coating white phosphorus with synthetic rub-ber. This coated product is called plasticized white phosphorus (PWP).

NOTEBoth WP and PWP can be extinguished by immersion in water. To prevent reig-nition after drying, copper sulfate can be added.

A-3.3.5.8. Nonfragmenting Target Practice (VT-NONFRAG). These projectiles (Figure A-28) are designed for use in antiaircraft target prac-tice, particularly against expensive drone targets, for observing the firing results, frequently without loss of the drone. A standard projectile body is filled with inert material around the color burst unit to obtain the desired weight. The nose of the pro-jectile is fitted with a VT-RF, proximity fuze, which is supplemented either by a fuze booster or an AD fuze. A self-destruct capability is incorpo-rated into the nose fuze of projectiles D248 and D249. The self-destruct feature is omitted in pro-jectiles D250 and D251. A fuze cavity liner sepa-rates the fuze from the color burst unit and inert filler. The color burst is ignited through the action of the nose fuzing and the black-powder pellets. The base of the projectile is either plugged or solid.

A-3.3.5.9. Target Practice (Puff) (TP-Puff).

THE SMOKE PRODUCED BY THE CHEMICAL MIXTURE USED IN A TARGET PRACTICE (PUFF) PROJECTILE CONTAINS HYDROCHLORIC ACID, WHICH IS EXTREMELY IRRITATING TO THE LUNGS, EYES, AND MUCOUS MEMBRANES. IN THE EVENT SMOKE OR CORROSIVE BUILDUP IS DISCOVERED COM-ING FROM A PUFF PROJECTILE, THE ROUND SHOULD BE DIS-POSED OF SAFELY. THE HAZ-ARDS ASSOCIATED WITH THE SMOKE CAN BE REDUCED WITH A WATER SPRAY. ON-BOARD SHIP, THE ROUND CAN BE DISPOSED OF AT SEA. ON LAND, THE ROUND CAN BE

Figure A-27 5-Inch, 38-Caliber White Phosphorus Projectile

Figure A-28 5-Inch, 38-Caliber Nonfragmenting Target Practice Projectile

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A-23

MOVED TO AN OPEN AREA FOR DISPOSAL BY EXPLOSIVE ORD-NANCE DISPOSAL PERSONNEL.

This is a nonexplosive, smoke producing pro-jectile (Figure A-29), that is used as a practice (spotting) round. A standard projectile body is filled with inert material around the smoke agent containers. The nose of the projectile is fitted with a MT or PD fuze and an AD fuze. The inert filled body has a 2-inch-diameter aluminum tube down the center, with one metal can or two Teflon bottles of smoke agent potted at the base end with epoxy. The inert load of the projectiles is Filler E, com-prised of stearic acid, barium sulfate, dead burned gypsum, and wood resin. The smoke producing chemicals, a 50/50 mixture of vanadium oxytrichloride and titanium tetrachloride, are con-tained in the Teflon bottles or metal cans. The base plug has been modified by removing all but one and one-half threads so that, on fuze function, the threads shear and the base plug and chemicals are expelled through the base of the projectile. The chemicals from the ruptured bottles or metal cans react with the moisture in the air, producing a dense yellowish smoke cloud that approximates the size of the smoke cloud from a high explosive round.

A-3.3.5.10. Chaff Dispensing. These projectiles (Figure A-30) are used to confuse enemy radar. They may be employed to provide a reflecting screen behind which ships may maneuver or they may be used to provide a false target. The projec-tile consists of an illuminating projectile body with

a nose time fuze and an expelling charge of black powder. Ignition of the expelling charge by the fuze discharges a payload of foil strips that reflect the radar beams. The useful lifetime of a chaff cloud is generally 10 minutes, provided that: (a) the cloud attains the maximum size 15 seconds after the chaff is dispensed at a selected fuze time, (b) the fall rate factor is 2 feet per second, and (c) the wind turbulence is at a minimum.

A-3.3.5.11. Blind Loaded and Plugged/Tracer (BL-P/T). The standard thin-walled projectile body is filled with inert material to bring it within the weight tolerance of the service projectile. The nose of the projectile is fitted with a dummy nose plug, while a plug is installed flush with the base of the projectile. Tracers are no longer assembled in new production. These projectiles are for target practice, ranging, and proving ground tests.

A-3.3.5.12. Dummy. These projectiles are used for loading drills and for testing the gun mount ammunition handling system. The dummy projec-tile (MK 1, MK 2, or MK 4 all MODs) uses a stan-dard projectile body filled with an inert material to bring it within the weight tolerance of the service projectile. The nose can have either a dummy nose plug or an inert MT fuze. The main difference between the dummy projectile and the blind loaded and plugged tracer projectile is that the dummy projectile has the copper rotating band turned down to the diameter of the projectile bourrelet to pre-vent engaging the rifling of the gun barrel.

Figure A-29 5-Inch, 38-Caliber Target Practice (Puff) Projectile

Figure A-30 5-Inch, 38-Caliber Chaff Dispensing Projectile

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A-24

A-3.3.6. Propelling Charge. The propelling charge is that component of the complete round that provides the force to propel the projectile from the gun to the target. Assembly of the propelling charge in a single, rigid, protective case increases the ease and rapidity of loading and reduces the danger of flare-backs. Also, case-loaded ammuni-tion prevents the escape of gases toward the breech of the gun. The case expands from the heat and pressure of the exploding propellant and forms a tight seal against the gun barrel chamber. Table A-3 is a listing of variations that are available, either through material change, means of manufacturing, method of assembly, or specialized application.

A-3.3.6.1. Full or Reduced Charge. The pro-pelling charge, full or reduced (Figure A-31) con-sists of a brass or steel cartridge case of a straight taper design. The propelling charge is assembled with a MK 48 primer (electric). It is loaded with 15.5 (SPD) or 17.0 (SPCF) pounds of smokeless

powder in the full charge and 4 pounds of propel-lant in the reduced charge. A cardboard wad and a distance piece, secured by a cork or polyurethane foam closure plug, serve to hold the propellant in place and complete the unit. The distance pieces are cut to the required length as governed by the propellant PPD.


Type Cartridge Case PrimerPropellant

Closure Plug DODICType Weight

(lbs.)

MK 63 MK 10/0 Full Charge Univer-sal

1 Steel MK 48 MOD 4 Electric SPCF 17.0 MK 2 CorkMK 11 Polyurethane

D264

Full charge non-flashless

MK 5 BrassMK 8 BrassMK 10/0,1 SteelMK 11/1,Spiral-Wrap

MK 13 CombinationMK 48 MOD 2 Electric

SPDN (M-6)SPD

15.5 MK 2 CorkMK 11 Polyurethane

D272

Full charge, flash-less

MK 10/0, 1 Steel MK 48 MOD 2 Electric SPDN (M-6)SPDF

15.5 MK 2 CorkMK 5 CorkMK 11 Polyurethane

D274

MK 64 MOD 0Reduces charge,nonflashless

MK 5 BrassMK 10/0,1

MK 13 CombinationMK 48 MOD 2 Electric

SPDN 4.0 MK 2 CorkMK 5 Cork

D282

MK 64 MOD 1Reduced charge, flashless

MK 10/1 Steel MK 48 MOD 2 Electric - 4.0 MK 11/1 Polyurethane D282

Clearing MK 5 Brass Modified MK 13 Combination SPDF 9.0 MK 2 Cork D227

Clearing MK 6 Brass Modified MK 13 Combination SPDF 9.0 Cork D306

MK 65 MOD 1 Clearing

MK 9 Steel Modified MK 48 MOD 2 Electric SPCF 10.0 MK 27 MOD 0 Elasto-meric

D296

Test cartridge MK 9 or 10 Steel Modified

MK 15 Lock - - - DW40

Figure A-31 5-Inch, 38-Caliber Propelling Charge

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A-25

A-3.3.6.2. Clearance Charge. The clearing charge (short charge) is similar to the full and the reduced charges, the major difference being that the cartridge case is 6.7 inches shorter. Clearing charges are used to clear guns by firing out projec-tiles after a propelling charge misfires or a loading jam occurs. The D296 charge differs from the D227 and the D306 charges in that if has coned polyurethane or elastomeric foam closure plug instead of the flat cork closure plug and it uses a polyethylene wad and bonds the wad to the car-tridge case sidewall instead of using a cardboard was and a distance piece. The D296 clearing charge is identified and issued as a common 5-inch (5-inch, 38 caliber/5-inch, 54 caliber) clearing charge. It is the only 5-inch clearing charge being procured.

A-3.3.7. Packing. The ammunition is handled and shipped according to OP 4 and OP 5. The ammunition is painted, marked, and lettered according to WS 18782. The following palletizing requirements apply:

A-3.3.8. Ballistic Data. The ballistic data for the 5-inch, 38 caliber projectile are as follows:

A-3.3.9. Average Muzzle Velocity.

A-3.3.9.1. Maximum Range.

A-3.4. 5-Inch, 54-Caliber Ammunition. The 5-inch, 54 caliber ammunition described

in this chapter fits within the separated ammunition category since the projectile and the propelling charge are two separate components, but they are loaded with the gun chamber in a single operation (i.e., one-ram cycle). The 5”/54 conventional ammunition can be used in either 5”/54 or 5”/62. A complete round of ammunition consists of the projectile and a propelling charge that is packed, shipped, and issued separately. This system is used as a tactical weapon against surface and air targets and for shore bombardment.

A-3.4.1. Ammunition/Interface. The 5-inch, 54 caliber ammunition is used in the MK 45 Single (lightweight), with a MK 19 barrel. The MK 45 MODs 0 and 2 may fire at a rate of 20 rounds per minute. The MK 45 MOD 4 fires conventional (the entire 5-inch, 54 caliber family) ammunition at the same rate. Because the primer is an electric one, the firing pin does not need to strike the primer, simply contact it firmly enough to allow the electrical current to flow. The firing pin extends slightly from the breech face and scrapes lightly across the case base and primer as the breech closes. The dimple seen in the primer on fired rounds is caused by the recoiling case pushing against the firing pin. Indeed, a misfired round will not show the dimple, but only a slight scratch.

A-3.4.2. Packing. The ammunition is handled and shipped according to OP 4 and OP 5. The ammunition is painted, marked, and lettered in accordance with WS 18782.

A-3.4.3. Ballistic Data. The ballistic data for this cartridge are listed as follows:

Projectile Requirement

Standard MIL-STD-1323-4Rocket assisted MIL-STD-1323/136C

Propelling Charge Requirement

Tanking OR-68/42Palletizing MIL-STD-1323/3-1


Muzzle Velocity

MK 49 or MK 51 Full-service 2,500 feet per secondMK 49 or MK 51 Reduced 1,200 feet per secondRAP Full-service 2,500 feet per second

Projectile PropellingCharge Range

MK 49 or MK 51 Full-service 17,393 yardsMK 49 or MK 51 Reduced 8,874 yardsRAP Full-service 26,657 yards

PROJECTILE REQUIREMENT

RAP WS 11475, Section 5

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A-26

A-3.4.3.1. Average Muzzle Velocity.

A-3.4.3.2. Maximum Range.

A-3.4.4. Projectiles. The projectiles used in the 5-inch, 54 caliber ammunition are described in the following subordinate paragraphs.

A-3.4.4.1. Antiaircraft Common (AAC). This steel body projectile (Figure A-32) is designed for use against Airborne or surface targets that are vul-nerable to air-bust. The projectile body nose and base are threaded and internally fitted with nose and base fuzing to provide increased detonation reliability. The nose is fitted with a fuze adapter and an MT and AD fuze. The projectile cavity is filled with either Explosive D or Composition A-3.

A-3.4.4.2. Rocket Assisted Projectile (RAP).

DURING HANDLING OF A RAP, A DROP IN EXCESS OF 24 INCHES ON THE BASE OF THE PROJEC-TILE IN WHICH A DECK PIN

(RIVETHEAD), BOLT, OR MIS-CELLANEOUS OBJECT STRIKES THE CENTER HOLE OF THE IGNITER, SUFFICIENT STRIK-ING ENERGY COULD BE PRO-VIDED TO ACTUATE THE IGNITER. IN THIS EVENT, IGNI-TION OF THE ROCKET MOTOR MAY BE DELAYED 20 TO 30 SEC-ONDS. ALL PERSONNEL SHOULD IMMEDIATELY EVAC-UATE THE AREA. DO NOT ATTEMPT DISPOSAL PRIOR TO ROCKET MOTOR IGNITING. IF THE ROCKET MOTOR BURNS IN A CLOSED COMPARTMENT, ENSURE THAT THE AREA IS CLEAR OF FUMES PRIOR TO RE-ENTRY. DISPOSE OF THE PROJECTILE IN ACCORDANCE WITH STANDARD EXPLOSIVE ORDNANCE DISPOSAL PRAC-TICE.

EXTREME CAUTION MUST BE USED IN FIRING OPERATIONS. ENSURE THE CORRECT IDENTIFI-CATION OF RAP PROJECTILES BECAUSE OF THE SIMILARITY OF PROJECTILE APPEARANCE AND THE DISSIMILARITY OF IMPACT POINTS OF A RAP COMPARED TO STANDARD PROJECTILES.

The projectile (Figure A-33) is made up of a solid propellant rocket motor (MK 64) with a delay ignition element and a centrifugal variable-time fuzed warhead (MK 78), designed for use against personnel and light material targets. The RAP can be handled, stowed, and fired almost identically to the conventional 5-inch projectiles now in use and is propelled by the same charge. The 5-inch, 54 caliber MK 58 RAP has the same shape as the standard projectile. To ensure ignition reliability, the 5-inch, 54 caliber RAP must be fired with a propelling charge having a 1-inch-diameter by 2-5/8 inch-deep hole centered in the front face of the closure plug. Propelling charges equipped with

PROJECTILE PROPELLINGCHARGE MUZZLE

VELOCITY

RAP Full-service 2,650 feet per second

PROJECTILE PROPELLING CHARGE RANGE

RAP Full-service 31,920 yards

Figure A-32 5-Inch, 54 Caliber Antiaircraft Common Projectile

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A-27

either cork or polyurethane plugs with holes will normally be supplied by a depot. The rocket motor is ignited when the gas pressure generated by the propelling charge propellant flexes a belleville spring, which strikes a percussion primer assembly, initiating the pyrotechnic delay column. After a 23-second delay, the delay column burns the ignition charge, which ignites the propellant grain in the rocket motor. When the motor is ignited, the igniter, which is sealed into the motor case base with a gas check gasket, is blown out. The rocket assistance extends the projectile range by approximately 6,300 yards.

A-3.4.4.3. Common (COM). The COM projec-tile (Figure A-34) is designed to penetrate approxi-mately one-third of its caliber of armor. This projectile has both a base plug and a base detonat-ing fuze. Once inside the target, the delayed-action base fuze functions to detonate the explosive filler. Prior to modern GFCS technology, various colored

spotting dyes were used to identify firing accuracy. Dyes are no longer required, and issues may or may not have dyes included. The projectile, which is made of forged steel, is loaded with 2.14 pounds of Explosive D.

A-3.4.4.4. Chaff Dispensing. These projectiles (Figure A-35) are used to confuse enemy radar. They may be employed to provide a reflecting screen behind which ships may maneuver, or they may be used to provide a false target. The projec-tile consists of an illuminating projectile body with a nose time fuze and an expelling charge of black powder. Ignition of the expelling charge by the fuze discharges a payload of foil strips that reflect the radar beams. The useful lifetime of a chaff cloud is generally 10 minutes, provided that: (a) the cloud attains maximum size 15 seconds after the chaff is dispensed at a selected fuze time, (b) the fall rate factor is 2 feet per second, and (c) the wind turbulence is at a minimum.

A-3.5. 6-Inch, 47-Caliber Ammunition.This section describes the 6-inch, 47 caliber

separate-loaded ammunition. The 6-inch, 47 cali-ber system was developed as a surface or air defense weapon, but like other gun ammunition systems, has out-lived its effectiveness as an anti-aircraft defense weapon. See Table A-4 for Projec-tile Data.

Figure A-33 5-Inch, 54-Caliber Rocket Assisted Projectile


Figure A-35 5-Inch, 54-Caliber Chaff Dispensing Projectile

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A-28

A-3.5.1. Projectiles. The basic configurations of projectiles in the 6-inch, 47 caliber ammunition are as follows:

A-3.5.2. Propelling Charges. The 6-inch, 47 caliber propelling charges are as follows:

A-3.5.3. Ammunition/Interface. The MK 16 MOD 0 gun system for 6-inch, 47 caliber ammuni-tion was a slow-fire, triple-turret system. This sys-tem had a maximum firing rate of 18 rounds per minute for each barrel (54 rounds per minute, per triple turret) in the automatic mode with the gun fixed at the loading angle or 10 rounds per minute for each barrel if fired at any other than the loading angle.

A-3.5.4. Ammunition Characteristics. A com-plete round of 6-inch, 47 caliber ammunition con-sisted of a projectile and a propelling charge, which was packed, shipped, and issued as two separate items. Data on the projectiles used for the MK 16 MOD 0 gun system and the propelling charges are given in the following paragraphs.

A-3.5.4.1. Projectiles. The same projectile body (MK 34/40) is used for all of the high explosive projectiles. The thin-walled projectile is filled with 13.1 pounds of Explosive D. The projectile body is made of ductile steel and has low-fragmentation properties. A variety of fuze combinations fit the


Type Projectile Body

Explosive Fuze Total Wt. (lbs.)

(Approx.)Filler Wt. (lbs.) Nose AD Base

AAC MK 34 or 40 Expl-D 13.17 MK 50 (MT) MK 54 MK 28 or 31 104.5

HC MK 34 or 40 Expl-D 13.17 Plugged MK 54 MK 28 or 31 103.7

HC MK 34 or 40 Expl-D 13.17 MK 29 (PD) MK 54 Plugged 103.7

HC MK 34 or 40 Expl-D 13.17 MK 29 (PD) MK 54 MK 31 103.7

HE-CVT MK 34 or 40 Expl-D 12.85 M514A1/2 (CVT) MK 52 Plugged 104.3

AP MK 35 Expl-D 1.95 – – MK 21 130.0

ILLUM MK 41 Black powder 4.511 MK 25 (MT) – – 116.0

BL-P/T MK 36, 37, 42, or 43

– – – – Plugged or MK 5 Tracer

130.0

1 Measured in ounces.

Projectile Abbreviation

Antiaircraft, mechanical time AACHigh capacity, plugged HCHigh capacity, point detonating, base plugged or low performance base deto-nating

HC-PD

High capacity, point detonating, base det-onating

HC

High explosive, controlled variable time HE-CVTArmor piercing Illuminating APIlluminating ILLUM

Clearing charge, cork plug (RF/SF) Blind loaded and plugged, tracer

BL-P/T

Full charge, flashless, plastic plug (RF/SF)Full charge, flashless, cork plug (SF)Full charge, nonflashless, plastic plug (RF/SF)Full charge, nonflashless, cork plug (SF)

Reduced charge, flashless, plastic plug (RF/SF)Reduced charge, flashless, cork plug (SF)Reduced charge, nonflashless, plastic plug (RF/SF)Reduced charge, nonflashless, cork plug, (SF)

Full charge, flashless, plastic plug (RF/SF)

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A-29

internally threaded nose and base. An AP, a BL-P, and an ILLUM projectile were available for the 6-inch, 47 caliber ammunition. Additional descrip-tions of these projectiles are given in Table A-2.

A-3.5.4.2. Antiaircraft Common (MC). This projectile (Figure A-36) was designed for use against airborne or surface targets vulnerable to airburst. The nose of the projectile body was threaded internally and fitted with MT and AD fuzes. The base of the projectile was also threaded internally and fitted with a BD fuze. The base fuze functioned by igniting and detonating the projectile main charge on target impact, unless prior detona-tion had been caused by nose fuze action.

A-3.5.4.3. High Capacity (HC). This projectile (Figure A-37) was designed for use against surface targets vulnerable to impact burst. The projectile was issued with either a dummy nose plug or with a PD fuze (MK 29) installed. The MK 29 fuze was installed aboard ship for the projectile issued with the dummy nose plug installed. A BD fuze or base fuze plug was fitted in the projectile base. A-3.5.4.4. High Explosive, Controlled Variable Time (HE-CVT). This projectile (Figure A-38) was designed for shore bombardment use against personnel and light material targets. The nose of the projectile body was fitted with CVT and AD fuzes separated from the explosive charge by a cavity liner. The base of the projectile was fitted with a base fuze plug.

A-3.5.4.5. Illuminating (ILLUM). This projec-tile (Figure A-39) was designed to deploy a para-chute-suspended pyrotechnic candle for target illumination. The thin-walled projectile nose was threaded internally and fitted with an MT fuze. The fuze served to ignite a 4.5-ounce expelling charge of black powder that sheared the base plate retaining pins and forced out the illuminating assembly; the fuze also ignited the candle. The illuminating candle composition was powdered magnesium mixed with oxidizer. The candle pro-duced a candlepower of 600,000 lumens and had a burning time of 50 seconds.

A-3.5.4.6. Armor Piercing (AP). This AP pro-jectile MK 35 (Figure A-40) was designed to pene-trate hard targets by using kinetic energy of impact. Once inside the target, the delayed action base fuze functioned to detonate the explosive filler. The projectile body was made of forged steel and was loaded with 1.9 pounds of Explosive D. The AP projectile was comprised of a body, a windshield, an AP cap, a BD fuze, and a base plug.

Figure A-36 6-Inch, 47-Caliber Antiaircraft Common Projectile


Figure A-38 6-Inch, 47-Caliber High Explosive-Controlled Variable Time Projectile

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A-30

A-3.5.4.7. Blind Loaded and Plugged/Tracer (BL-P/T). This projectile was used for target prac-tice, ranging, and proving ground tests. It was designed so that it would be similar in exterior shape, weight, and balance to correspond with ser-vice projectiles. The projectile body was made of steel with an external thread machined on the nose

to receive a nose cap (windshield). This projectile could be requisitioned with or without spotting dye (blue, green, red, or orange colored) positioned in the void area under the windshield. The base of the projectile body was threaded internally to receive either a base plug or internal orange colored tracer.

A-3.5.5. Propelling Charge. Data for the pro-pelling charges are given in Table A-5. The pro-pelling charge, full or reduced, (Figure A-41) consisted of a brass or steel cartridge case of a straight taper design. This charge was assembled with the MK 13 primer (combination) or the MK 39 primer (electric) in the full service charge and the MK 40 primer (electric) in the reduced charge. The cartridge case was loaded with a nom-inal 33.5 pounds of smokeless powder (propellant) in the full service charge and a nominal 21.3 pounds of propellant in the reduced charge. A cardboard wad and a distance piece, secured by a cork or plastic closure plug, served to hold the pro-pellant in place. The distance pieces were cut to the required length as governed by the propellant production packing depth.


Figure A-40 6-Inch, 47-Caliber Armor-Piercing Projectile

Figure A-41 6-Inch, 47-Caliber Gun Propelling Charge Assembly



Closure PlugType Weight

(lbs.)

Full charge, nonflashless, SF/RF MK 6 MODs BrassMK 7 Steel

MK 39 MODs SPD 33.5 MK 4 MOD 1 Plastic

Full charge, flashless, SF/RF MK 6 MODs BrassMK 7 MODs Steel

MK 39 MODs SPDFSPDN

33.5 MK 4 MOD 1 Plastic

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A-31

A-3.5.6. Packing. The ammunition was handled and shipped according to OP 4 and OP 5. The ammunition was painted, marked, and lettered according to WS 18782.

A-3.5.7. Ballistic Data. The ballistic data for the 6-inch, 47 caliber round are as follows:

A-3.5.7.1. Muzzle Velocity. The average muzzle velocity was as follows:

A-3.5.7.2. Range. The maximum range was as follows:

A-3.6. 8-Inch, 55-Caliber Ammunition. This section describes the 8-inch, 55 caliber separated ammunition. A complete round of ammunition consisted of two units: the projectile assembly and the propelling charge assembly. The 8-inch, 55 caliber triple-gun turret of the CA-139 class was installed on the largest heavy cruiser in the fleet.

Full charge, nonflashless, SF MK 4 MODsMK 6 MODs Brass

MK 13 MODsMK 39 MODs

SPD 33.5 MK 2 MOD 0MK 3 MOD 0

Full charge, flashless, SF MK 4 MODsMK 6 MODs Brass

MK 13 MODsMK 39 MODs

SPDF 33.5 MK 2 MOD 0MK 3 MOD 0 Cork

Reduced charge, nonflashless, SF/RF

MK 6 MODs Brass MK 40 MODs SPDN 21.3 MK 4 MOD 1 Plastic

Reduced charge, flashless, SF/RF MK 6 MODs Brass MK 40 MODs SPDF 21.3 MK 4 MOD 1 Plastic

Reduced charge, nonflashless, SF/RF

MK 6 MODs Brass MK 40 MODs SPDF 21.3 MK 2 MOD 0MK 3 MOD 0 Cork

Reduced charge, flashless, SF/RF MK 6 MODs Brass MK 40 MODs SPDF 21.3 MK 2 MOD 0MK 3 MOD 0

Clearing charge, flashless, SF/RF MK 4/0, MK 6 MODs Brass (Modified)MK 7, Steel (Modified)

MK 13 MODsMK 40 MOD 1

SPDF 25.0 MK 2 MOD 0MK 3 MOD 0 Cork

Dummy propelling charge, SF, MK 2 MOD 0

MK 6 Brass - - - Bronze

Dummy propelling charge, RF, MK 3 MOD 0

MK 6 Brass - - - Bronze



Closure PlugType Weight

(lbs.)

Projectile PropellingCharge Muzzle Velocity

HE-AAC Full-service 2,665 feet per secondHE-HC Full-service 2,665 feet per secondHE-CVT Full-service 2,665 feet per secondAP Full-service 2,500 feet per secondILLUM Full-service 2,575 feet per secondBL-P/T Full-service 2,500 feet per second

Projectile Propelling Charge Range

HE-AAC Full-service 23,483 yardsHE-HC Full-service 23,483 yardsHE-CVT Full-service 23,483 yardsAP Full-service 26,118 yardsILLUM Full-service NABL-P/T Full-service 26,118 yards

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A-32

This system was capable of engaging sea or land targets and could be operated by hand, local, or automatic control.

A-3.6.1. Projectile (Rapid Fire). The basic configurations of the projectile in 8-inch, 55 cali-ber ammunition are as follows:

A-3.6.2. Propelling Charge. The basic configu-rations of 8-inch, 55 caliber propelling charges are as follows:

Full charge, flashless (RF)Full charge, nonflashless (RF)Full universal (RF)Reduced, flashless (RF)

Reduced, nonflashless (RF)Reduced, nonflashless (RF)Clearing (RF)Dummy (RF)

A-3.6.3. Ammunition/Interface. The 8-inch, 55 caliber gun interfaced with the MK 16 MOD 0 rapid fire, triple-gun turret.

A-3.6.4. Ammunition Characteristics.

A-3.6.4.1. Projectiles. Data for the 8-inch, 55 caliber projectiles are given in Table A-6.

A-3.6.4.2. High Capacity, Point Detonating/Dummy Nose Plug (HC-PD/DNP). These low-fragmentation, thin-walled, steel body projectiles (Figure A-42) were designed for use against unar-mored surface targets or shore installations vulner-able to impact burst. The projectile cavity was filled with Explosive D. HC projectiles were issued with either a dummy nose plug or with a PD fuze installed. Blast and fragmentation effects were obtained when this projectile was used with a PD fuze installed in the nose, and limited penetration effects were obtained when this projectile was used with a dummy nose plug installed.


High capacity, dummy nose plug HCHigh capacity, point detonating HC-PDHigh explosive, controlled variable time

HE-CVT

Common, base detonating COMArmor piercing APBlind loaded and plugged/tracer BL-P/T


Projectile Explosive Fuze Total Weight (lbs.)

(Approx.)Type Body Filler Wt. (lbs.) Nose AD Base

HC MK 24 Expl-D 21.3 Plug MK 54 or 55 MK 21/1,3 258.8

MK 25 Expl-D 21.3 Plug MK 54 or 55 MK 21/1,3 258.8

MK 24 Expl-D 21.3 Plug MK 54 or 55 MK 48 258.8

MK 25 Expl-D 21.3 Plug MK 54 or 55 MK 48 258.8

HC-PD MK 24 Expl-D 21.3 MK 29 MK 54 or 55 Plug or 260.0

MK 25 Expl-D 21.3 MK 29 MK 54 or 55 LP fuze 260.0

MK 24 Expl-D 21.3 MK 29 MK 54 or 55 MK 48 260.0

MK 25 Expl-D 21.3 MK 29 MK 54 or 55 MK 48 260.0

HE-CVT MK 24 Expl-D 21.3 M514A1 MK 52 Plug or 260.0

MK 25 Expl-D 21.3 M514A1 MK 52 LP fuze 260.0

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A-33

A-3.6.4.3. High Explosive, Controlled Variable Time (HE-CVT). The projectile (Figure A-43) body was made of ductile steel having low-frag-mentation properties. The nose and base of the projectile body were threaded internally and fitted with a CVT fuze in the nose and a plug in the base. The nose fuze was separated from the projectile cavity explosive by a cavity liner that permits fuze replacement without the use of remote equipment.

The VT fuze provided an airburst capability for increased fragmentation effects against surface tar-gets.

A-3.6.4.4. Common (COM). This projectile (Figure A-44) was designed to penetrate approxi-mately one-third its caliber of armor. The COM projectile differed from the AP in that it had no hardened cap and had a larger explosive cavity. The projectile base was fitted with a BD fuze with a 0.033-second delayed action feature to allow the projectile to penetrate the target before the fuze functioned to detonate the explosive filler. The projectile body was made of forged steel and loaded with 11.4 pounds of Explosive D.

A-3.6.4.5. Armor Piercing (AP). This projectile (Figure A-45) was designed to penetrate hard tar-gets by using kinetic energy of impact. Once inside the target, the 0.033-second delayed action base fuze functioned to detonate the explosive filler. The projectile body was made of forged steel and was loaded with 1.9 pounds of Explosive D. The AP projectile was comprised of a body, a windshield, an armor-piercing cap, a BD fuze, and a base plug.

COM MK 14 Expl-D 11.4 – – MK 19 or 21 277.1

MK 15 Expl-D 11.4 – – MK 19 or 21 277.1

MK 17 Expl-D 11.4 – – MK 19 or 21 277.1

AP MK 21 Expl-D 5.1 – – MK 21 335.0

MK 19 Expl-D 3.6 – – MK 21 260.0

BL-P/T1 MK 16 Inert – – – – 277.1

MK 16 Inert – – – – 277.1

MK 18 Inert – – – – 277.1

MK 19 Inert – – – –

MK 21 Inert – – – – 277.1

MK 22 Inert – – – – 277.1

MK 27 Inert – – – – 277.1

1 Inert AP projectiles


Projectile Explosive Fuze Total Weight (lbs.)

(Approx.)Type Body Filler Wt. (lbs.) Nose AD Base


SW030-AA-MMO-010

A-34

A-3.6.4.6. Blind Loaded and Plugged/Tracer (BLP/T). This projectile was used for target prac-tice, ranging, and proving ground tests. It had a similar exterior, shape, weight, and balance to the service projectiles. The projectile body was made of steel with an external thread machined on the nose to receive a nose cap (windshield). This pro-jectile could be requisitioned with or without spot-ting dye (blue, green, red, or orange colored) positioned in the void area under the windshield. The base of the projectile body was threaded inter-nally to receive either a base plug or an internal orange colored tracer.

A-3.6.5. Propelling Charge. Table A-7 is a list-ing of propelling charge variations that were avail-able, either through material change, means of manufacturing, method of assembly, or specialized application.

Figure A-43 8-Inch, 55-Caliber Projectile High Explosive Controlled Variable Time



Table A-7 8-Inch, 55-Caliber Propelling Charge Data

Type Cartridge Case Primer

PropellantClosure Plug

Type Weight (lbs.)

Full charge, nonflashless, SF/RF MK 1 Brass MK 37 SPD/SPDN 78 MK 1 Plastic orMK 4 Polyurethane

Full charge, flashless, RF MK 1 Brass MK 37 SPCG/SPDF

78 MK 1 Plastic orMK 4 Polyurethane

Full charge, universal, RF MK 1 Brass MK 37 SPCF 84 MK 1 Plastic orMK 4 Polyurethane

Reduced charge, flashless, RF MK 1 Brass MK 38 SPDF 44.5 MK 1 Plastic orMK 4 Polyurethane

Reduced charge, nonflashless, RF MK 1 Brass MK 38 SPDN 44.5 MK 1 Plastic orMK 4 Polyurethane

SW030-AA-MMO-010

A-35

A-3.6.5.1. Full or Reduced Charge. The pro-pelling charge (Figure A-46), full or reduced, con-sisted of a brass cartridge case of a straight taper design. It was assembled with a MK 37 primer (electric) in the full service charge and with a MK 38 primer (electric) in the reduced charge. The charges were loaded with approximately 78 pounds of pyro or 84 pounds of NACO propellant in the full service charge and 44.5 pounds of pyro propellant in the reduced charge. Charges assem-bled with the MK 1 plastic closure plugs had bonded pyralin wads to secure the propellant bed, while charges assembled with the MK 4 polyure-thane closure plugs had polyethylene (unbonded) wads and cardboard distance pieces to secure the propellant beds. Charges loaded with pyro propel-lant had decoppering lead foil positioned in the void space between the wad and the closure plug. The distance pieces were cut to the required length as governed by the propellant production packing depth.

A-3.6.5.2. Clearing Charge. The clearing charge (short charge) was similar to the full and reduced charges; the major difference was that the charge was 19.2 inches shorter. Clearing charges

were used to clear guns by firing out projectiles after a propelling charge misfire or loading jam occurrence.

A-3.6.6. Packing Data. The ammunition was handled and shipped according to OP 4 and OP 5. The ammunition was painted, marked, and lettered according to WS 18782.

A-3.6.7. Ballistic Data. The ballistic data for the 8-inch, 55 caliber projectile are as follows:

A-3.6.7.1. Muzzle Velocity. The average muzzle velocities were the following:

A-3.6.7.2. Range. The maximum ranges were the following:

A-3.7. 16-Inch, 50-Caliber Ammunition. The 16-inch, 50 caliber triple-turret gun of the BB 61 class ships was developed to house the largest United States naval guns. This gun (bag) was the largest of the separate loading ammunition guns. A complete round of ammunition consisted of a pro-jectile, powder bags, and a combination lock primer, which were loaded in the gun separately.

Reduced charge, nonflashless, 6-in., 47 caliber propellant, RF

MK 1 Brass MK 38 SPDN 44.5 MK 4 MOD 0 Polyurethane

Clearing charge, RF MK 2 Brass MK 35/1 SPDF 44.0 MK 1 MOD 0 Plastic

MK 1 MOD 0 Dummy Propelling charge

MK 2 Brass - - - -

Table A-7 8-Inch, 55-Caliber Propelling Charge Data (Continued)

Type Cartridge Case Primer

PropellantClosure Plug

Type Weight (lbs.)

Figure A-46 8-Inch, 55-Caliber Gun Propelling Charge Assembly

Projectile (lb.)

Propelling Charge

Muzzle Velocity

260 Full-service 2,800 feet per second 335 Full-service 2,700 feet per second

Projectile (lb.)

Propelling Charge

Range

260 Full-service 31,982 yards 335 Full-service 30,360 yards

SW030-AA-MMO-010

A-36

This system had the capability of engaging sea and ground targets with local or remote control. See Table A-8 for projectile characteristics data.

A-3.7.1. Projectiles. The projectiles in the 16-inch, 50 caliber ammunition inventory were as fol-lows:

A-3.7.2. Propelling Charge. The propelling charges in the 16-inch, 50 caliber inventory were as follows:

Full charge, bagged, nonflashlessFull charge, bagged, nonflashlessReduced charge, bagged, flashlessDummy

A-3.7.2.1. Bag Charge. The 16”/50, which was in a 3 gun turret, used separate loading ammunition where the propelling charge was made up of sec-tions of powder contained in cylindrical cloth bags whose diameter was approximately the size of the gun chamber in which they were to be used. In the full charge (service charge) the propellant grains were stacked in the charge with the bag laced tightly around them. In most situations, more than one section (bag) was used. See Appendix A-3.7.2. for historical information about bag charges for the 16-inch guns.

A-3.7.3. Ammunition/Interface. The 16-inch, 50 caliber gun interfaced with the MK 7 MOD 0 rapid fire, three-gun turret. This system had a firing rate of two rounds per minute per gun.


A-3.7.5. Projectiles. The projectile was that component of ammunition that, when fired from a gun, carried out the tactical purpose of the weapon system. Projectiles also were used to illuminate targets at night or produce a chemical or smoke service as needed. Projectiles were classified by their tactical purpose. Data for the 16-inch, 50 cal-iber projectiles are given in Table A-8.


High capacity, electronic time HC-ETHigh capacity, controlled variable time

HC-CVT

High capacity, point detonating HC-PDHigh capacity, base detonating HC-BDHigh capacity, special, inert, auxil-iary detonating Antipersonnel

HC-S

Armor-piercing APBlind loaded and plugged/tracer BL-P/TBlind loaded and plugged BL-P

Table A-8 16-Inch, 50-Caliber Projectile Characteristics Data

Projectile Explosive Fuze Total

Weight (lbs.)

(Approx.)

DODICType Assembly1 Body Filler Wt.

(lbs.) Nose AD Base

HC-BD NA MK 13 Expl-D 153.5 Plug MK 55/0 MK 48/4 1,900 D878

NA MK 14 Expl-D 153.5 Plug MK 55/0 MK 48/4 1,900 D878

HC-S NA MK 13 Expl-D 153.5 Plug Inert MK 21/3 1,900 D879

NA MK 14 Expl-D 153.5 Plug Inert MK 21/3 1,900 D879

HC-ET MK 145/2 MK 13 Expl-D 153.5 MK 423 – MK 48/4 1,900 D880

HC-PD MK 140/0 MK 13 Expl-D 153.5 MK 29 MK 55/0 MK 48/4 1,900 D882

Antipersonnel MK 144/0 MK 19 RDX (A-5) 21.0 M724 – – 1,900 D775

AP MK 139/0 MK 8/6-8 Expl-D 40.5 – – MK 21/3 2,700 D862

NA MK 8/1-5 Expl-D 40.5 – – MK 21/3 2,700 D872

SW030-AA-MMO-010

A-37

A-3.7.5.1. High Capacity (HC). These HC pro-jectiles (Figure A-47) were designed for use against unarmored surface targets vulnerable to impact burst. They were used primarily to provide blast and fragmentation, but limited penetration could be obtained when used with a dummy nose plug. The projectile body was made of ductile steel having low-fragmentation properties. The nose and base fuzing threaded internally to accept nose and base fuzing. The projectiles were issued with a dummy nose plug or a PD, an AD, and a 10-millisecond delay BD fuze (MK 48). All varia-tions of the HC projectile cavities are filled with Explosive D. The principal variations in these pro-jectiles are described below.

A-3.7.5.1.1. High Capacity – Special. The HC special projectiles were issued with a dummy nose plug, an inert AD fuze, and a 33-millisecond delay BD fuze (MK 21).

A-3.7.5.1.2. High Capacity – Controlled Vari-able Time. The HC-CVT projectiles (Figure A-48) were designed for use against unarmored sur-face targets vulnerable to airburst. These projec-tiles were issued with a CVT fuze installed in the nose. The base was fitted with a 10-millisecond delay BD fuze (MK 48) for backup.

A-3.7.5.1.3. High Capacity – Electronic Time. The HC-ET projectiles (Figure A-49) were designed for use against unarmored surface targets vulnerable to airburst. These projectiles were issued with an M724 ET fuze with booster or MK 423 MOD 0 fuze installed in the nose. The base was fitted with a 10-millisecond delay BD fuze (MK 48) for backup.

A-3.7.5.1.4. High Capacity–Point Detonating. The HC-PD projectiles were designed for use against unarmored surface targets vulnerable to impact burst. They were issued with a PD and an

BL-P/T NA MK 9 Inert – Plug – – 2,700 D881

NA MK 18 Inert – Plug – – 2,700 D881

MK 141/0 MK 14 Inert – Plug – – 1,900 D873

BL-P MK 15 MK 13 Inert – Plug – – 1,900 D873

HC-CVT MK 143/0 MK 13 Expl-D 153.5 MK 732 – MK 48/4 1,900 D877

1 NA = Not assigned.

Table A-8 16-Inch, 50-Caliber Projectile Characteristics Data (Continued)

Projectile Explosive Fuze Total

Weight (lbs.)

(Approx.)

DODICType Assembly1 Body Filler Wt.

(lbs.) Nose AD Base


Figure A-48 16-Inch, 50-Caliber High Capacity Controlled Variable Time Fuzed Projectile

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A-38

AD fuze installed in the hose. The base was fitted with a 10-millisecond delay BD fuze (MK 48) for backup.

A-3.7.5.2. Antipersonnel.

G RE N A D E S A C C I D E N T A L L Y RELEASED FROM A PROJECTILE SHALL NOT BE HANDLED OR MOVED UNDER ANY CIRCUM-STANCES. PERSONNEL IN THE VICINITY OF EXPOSED GRE-NADES SHALL EVACUATE THE AREA IMMEDIATELY. EXPOSED GRENADES SHALL BE REPORTED TO QUALIFIED DISPOSAL PER-S O N N E L . A P RO J E CT I L E I S EXTREMELY HAZARDOUS IF THE BASE PL UG IS NO T IN PLACE. A COMPLETE GRENADE (WITH THE BALL IN THE HOUS-ING) IS EXTREMELY HAZARD-O U S W H E N O U T O F T H E PROJECTILE. A 1-FOOT DROP (OR EQUIVALENT SHOCK) ON THE YOKE OF AN ARMED GRENADE WILL ACTUATE THE GRENADE.

The antipersonnel projectile (Figure A-50) consisted of a projectile body, an expulsion charge, a pusher plate, a payload of 400 individually fuzed grenades, and a base plug. The projectile was fuzed, and a protective cap was installed at depot

level prior to issue to combatant ship. The base plug was press-fitted into the base of the projectile body and was secured by six shear pins. The M43A1 grenade is an airburst rebounding muni-tion. Each grenade is comprised of a housing assembly, a grenade body assembly, a primer, a fir-ing pin, and two spring-loaded vanes.

A-3.7.5.3. Armor Piercing. The AP projectile (Figure A-51) was designed to penetrate its caliber of class A armor plate and was designed to pene-trate hard targets by using kinetic energy of impact. Once inside the target, the delayed action base fuze functioned to detonate the explosive filler. The AP projectile was comprised of a body, a windshield, an AP cap, a BD fuze, and a base plug.

Figure A-49 16-Inch, 50-Caliber High Capacity Electronic Time Fuzed Projectile

Figure A-50 16-Inch, 50-Caliber Antipersonnel Projectile

Figure A-51 16-Inch, 50-Caliber, Armor-Piercing Projectile

SW030-AA-MMO-010

A-39

IF A 16-INCH PROPELLANT BAG OR IGNITION PAD IS RIPPED, TORN, OR OTHERWISE DAM-AGED, CEASE ALL OPERA-TIONS IN THE AFFECTED TURRET. IMMEDIATELY CON-TACT QUALIFIED DISPOSAL PERSONNEL. DISPOSE OF DAM-AGED BAG AND ANY SPILLED BLACK POWDER OR PROPEL-LANT GRAINS PER PARAGRAPH 2-102A OF OP 4, AMMUNITION AFLOAT.

THE D846 PROPELLING CHARGE IS AUTHORIZED FOR USE ONLY WITH THE 1,900-POUND PROJECTILE. A MIS-MATCH, THE D846 PROPELLING CHARGE WITH THE 2 ,700-POUND PROJECTILE, WILL RESULT IN AN INCREASE IN BARREL PRESSURE, MORE THAN SERVICE BUT LESS THAN PROOF PRESSURE. A DECREASE IN MUZZLE VELOC-ITY (2,434 FEET PER SECOND) WILL ALSO RESULT.

A-3.7.5.4. Blind Loaded and Plugged/Traced. This projectile was used for target practice, rang-ing, and proving ground tests. It had a similar exte-rior, shape, weight, and balance to correspond with service projectiles. The projectile body was made of steel with an external thread machined on the nose to receive a nose cap (windshield). The pro-jectile could be requisitioned with or without spot-ting dye (blue, green, red, or orange-colored) positioned in the void area under the windshield. The base of the projectile body was threaded inter-nally to receive either a base plug or internal orange-colored tracer.

A-3.7.5.5. Propelling Charge. The propelling charge was that component of the complete round that provides the force to propel the projectile from

the gun to the target. This system was the last of the bag charge gun systems in the United States Navy. Propelling charge data are given in Table A-9. The basic configurations were full and reduced charges.

A-3.7.5.6. Full or Reduced Charge. The pro-pelling charge, full or reduced, consisted of propel-lant [stacked grains (full charge), dumped grains (reduced charge)] contained in silk or acrylic rayon bags. The MK 15 primer (combination lock) and lead foil (decoppering agent) were issued sepa-rately. The full charges were issued with the wear-reducing jackets attached. A large quantity of pro-pellant was required to develop the initial projectile velocity required by this gun system. By dividing the required amount of propellant into several fab-ric bags, each of which could be handled by one person, the gun could be loaded in a relatively brief time. The bags were kept in airtight steel tanks until just before use. The combination primer was loaded manually into a firing lock attached to the gun breech plug.

A-3.7.5.7. Lead Foil. Between 1942 and 1945 all smokeless powder bag charges were assembled with lead foil (decoppering agent) packaged inside the powder bag. However, as the result of handling casualties, after 1 June 1945 the lead foil was a separate unit of issue with the lead foil placed inside a silk bag envelope and packaged in a 5-inch, 51 caliber tank. All previously loaded bag charges were reworked and the lead foil removed from the bag charge. When the gun was loaded, the lead foil was removed from the envelope and loaded into the gun chamber with the powder bags, positioned between the first and second sections toward the base of the projectile. Lead foil did, however, decrease the effectiveness of the flash less aspect of the flashless propelling charge. If the flashless aspect was required, the use of a decop-pering agent was left to the discretion of the fleet. The suggested usage for a 16-inch, 50 caliber charge was as follows:

Weight of lead foil per envelope.......200 gramsNumber of envelopes per charge .....................2Number of envelopes per tank ....................100

SW030-AA-MMO-010

A-40

A-3.7.5.8. Wear-Reducing Jackets. All 16-inch, 50 caliber full charge sections were fitted with a polyurethane wear-reducing jacket. These jackets consisted of a 15-inch-wide, 43-inch-long, and 0.156-inch-thick sheet of polyurethane wrapped around the outside of each bag charge section. An acrylic, viscose rayon cloth loop was sewn along the length of the polyurethane on both sides. This loop enclosed a silk tie cord that was used to secure the jacket to the bag charge section. The purpose of these jackets was to reduce gun barrel erosion thus extending the service life of the barrel.

A-3.7.6. Packing. The ammunition was handled and shipped according to OP 4 and OP 5. The ammunition was painted, marked, and lettered according to WS 18782. Separate components, such as some nose fuzes and primers for bag gun loads, were shipped individually in hermetically sealed cans.

A-3.7.7. Ballistic Data. The ballistic data for the 16-inch, 50 caliber projectiles are as follows:

A-3.7.7.1. Muzzle Velocity. The average muzzle velocities were as follows:

A-3.7.7.2. Range. The maximum ranges were as follows:

A-4. FUZE

A-4.1. Nose Fuzes.

A-4.1.1. Fuze M75 (T71E4) (20mm Point Det-onating).

FUZE M75 IS NOT BORESAFE AND SHOULD NOT BE USED.

Table A-9 16-Inch, 50-Caliber Propelling Charge Data

Type

Propellant IgnitionNumber of

Sections per Charge

Primer (lock) DODIC

Type Weight (lbs.)Black Powder

(grams per section)

Full charge, silk bag nonflash-less w/wear reducing liner

SPD 660 350 6 MK 15 D839

Full charge, silk or acrylic rayon bag, nonflashless w/wear reducing liner

SPD 600 350 6 MK 15 D846

Reduced charge, silk or acrylic rayon bag, flashless

SPCG 315 350 6 MK 15 D845

Reduced charge, silk or acrylic rayon bag, nonflashless

SPDN 315 350 6 MK 15 D840

MK 4 MOD 0 Dummy – – – 6 – D844


Muzzle Velocity

AP Full-service 2,500 feet per second

HC Full-service 2,690 feet per second

Projectile Propelling Charge Range

AP Full-service 40,185 yardsHC Full-service 41,622 yards

SW030-AA-MMO-010

A-41

A-4.1.2. General. The M75 fuze (Figure A-52) is provided for use with 20mm, high-explosive-incendiary ammunition. It is a single-action, superquick type intended to function with percussion action on impact with aircraft targets. Its design differs from the ordinary fuze in that functioning is initiated on impact by the set-forward force of the detonator charge, by pieces of metal from the body striking the detonator charge, by compression of the air column (with the accompanying formation of heat) forward of the detonator charge, or by a combination of any or all of these. Hence, the striker or firing pin mechanism usually found in point detonating fuzes is omitted in this design.

A-4.1.3. Description. The fuze is made up of two major parts, a body with an air space in the forepart of the fuze and a magazine containing the explosive train that is screwed into the base of the body to seat against an aluminum impact disc. The explosive train consists of a mercury fulminate det-onator charge, an intermediary charge of lead azide, and a tetryl base charge (booster). This fuze has the potential of forming copper azide deposits on brass parts after long-term storage and should be handled carefully.

A-4.1.4. Use.20mm HEI projectiles

A-4.1.5. Physical Characteristics.Drawing .............................................. 73-1-193Weight..........................................0.0497 poundLength ............................................. 1.20 inchesThread size................................0.5625-32NS-1

A-4.1.6. Explosive Components.Detonator .............................Mercury fulminateIntermediary charge ......................... Lead azideBooster..................................................... Tetryl

A-4.1.7. Arming.In-line explosive train

A-4.1.8. Function.Type ........................................ Point detonatingDelay............................................Instantaneous

A-5. PRIMERS

A-5.1. Primer MK 37 MODs (Electric).This series of primers was developed to pro-

vide a nonpercussion electric screw primer for use in 8-inch, 55 caliber separated ammunition.

A-5.1.1. Description. All MODs had a main charge of about 168.5 grains of black powder (class 2). MOD 1 superseded the MOD 0 because of its complicated design. MODs 1 and 2 (Figure A-53) consisted of a brass stock, an ignition element, and a seamless steel primer tube containing a main charge of class 2 black powder. The ignition element in the MOD 1 had an initiator consisting of a double-arm bridgewire in diazodinitrophenol and potassium chlorate with a booster charge of black powder. The ignition element in the MOD 2 was similar to that of the MOD 1 except that it used an initiating charge of lead styphnate and Scotchcast had been added to prevent pinching. It has been designated Ignition Element MK 1 MOD. See Figure A-10.

Figure A-52 Fuze M75 (Point Detonating), Cross-Sectional View

SW030-AA-MMO-010

A-42

Table A-10 Historic Primers by Mark and MOD with Assignment to Gun or Use

20mm 3 in. 50 cal.

5 in. 38 cal.

5 in. 54 cal.

6 in. 47 cal.

8 in. 55 cal.

Bag Gun(all cals.)

ie, 16” 50 cal.

MK 13 MOD 0, 1, 2 CC CC

MK 14 MOD 0, 1 CP

MK 15 MOD 1, 2, 3 LCT LCT LCT4 LC

MK 35 MOD 0, 1 CC1

MK 37 MOD 0, 1, 2 CE2

MK 38 MOD 1, 2 CE3

MK 39 MOD 0, 1, 2 CE2

MK 40 MOD 0, 1, 2 CE3

MK 41 MOD 0 CP

MK 42 MOD 0, 1, 2, 3, 4 CE

MK 44 MOD 0 CET CET CET

MK 48 MOD 0, 1, 2 CE

M36A1 PC

CE - Case ElectricCC - Case CombinationCP - Case Percussion

LCT - Lock Combination TestLC - Lock CombinationCET - Case Electric TestPC - Percussion Cap

1 - Short Charge Only2 - Full Charge Only3 - Reduced Charge Only4 - Still in Service

Figure A-53 Primer MK 37 MODs 1 and 2 (Electric), Cross-Sectional View

SW030-AA-MMO-010

A-43

A-5.1.2. Interface.8-inch, 55 caliber

A-5.1.3. Physical Characteristics.Design Data

Overall length MOD 0 ................................. 31.382 inches MOD 1 ................................. 31.180 inches MOD 2 ................................. 31.180 inchesBoss diameter ................................ 1.600 inches

Weight.......................................2.955 pounds Thread dimensions.................... 1.25-12NF-3Primer tube

Length........................................ 30.00 inches Unvented length .......................... 1.50 inches Vent diameter ................................. 0.25 inch No. of vents .............................................. 76Components

Stock ..................................................... Brass Plug....................................................... Brass Primer tube ............................................ SteelIgnition element

MOD 0................................ Drawing 398521 MOD 1................................ Drawing 584090 MOD 2.................................... MK 1 MOD 1

A-5.1.4. Explosive Data.Ignition charge

Diazodinitrophenol and potassium chlorate MOD 0................................................None MOD 1..................................45 milligrams MOD 2................................................None Lead styphnate MOD 0.................................................. NA MOD 1................................................None MOD 2...............................79.3 milligrams

Nitrocellulose MOD 0.................................................. NA MOD 1................................................None MOD 2.................................1.7 milligrams

Booster, class 4 black ...........230 milligrams powder

Primer tube, class 2 black powder MOD 0.......................................178 grams

MOD 1.......................................166 grams MOD 2....................................168.5 grams

A-5.1.5. Functioning Data.Primer resistance

MOD 0 .................................0.12 – 0.22 ohm MODs 1 and 2 ......................0.10 – 0.18 ohmRecommended current

Testing ................................... < 50 milliamps Firing.............................................> 10 amps Firing voltage ..........................20 Vac or Vdc Electrostatic sensitivity ...............8 x 105 ergs


A-5.1.6. Packing Data.LD 255254.......................................Inner pack,

5 primers per canDrawing 512849 ............................. Outer pack,

4 cans per containerMIL-STD-1322/851......................Palletization,


A-5.2. Primer MK 38 MODs (Electric).

A-5.2.1. General. Primers in this series were abbreviated versions of the MK 37 and were devel-oped to provide a nonpercussion electric screw primer for use in the 8-inch, 55 caliber reduced charge round.

A-5.2.2. Description. The MOD 1 superseded the MOD 0 because of the complicated design of the MOD 0. MODs 1 and 2 (Figure A-54) were similar to the MK 37 MODs 1 and 2 except that the primer tube had been shortened, and the class 2 black powder main charge had been reduced from 168.5 to 95.3 grams. MODs 1 and 2 consisted of a brass stock, an ignition element, and a seamless steel primer tube containing a black powder (class 2) main charge. The ignition element in the MOD 1 had an initiator consisting of a double-arm bridgewire in diazodinitrophenol and potassium chlorate with a booster charge of black powder. The ignition element in the MOD 2 was similar to

SW030-AA-MMO-010

A-44

that used in the MOD 1 except that it used an initi-ating charge of lead styphnate and had been desig-nated Ignition Element MK 1 MOD 0.


A-5.2.4. Physical Characteristics.Design Data

Overall length ............................18.93 inches Boss diameter...............................1.60 inches Weight.......................................1.948 pounds Thread dimensions.................... 1.25-12NF-3Primer tube Length ........................................17.75 inches Unvented length ..........................2.75 inches

Vent diameter .................................. 0.25 inch No. of vents ............................................... 40ComponentsStock......................................................... BrassPlug........................................................... BrassPrimer tube ................................................ SteelIgnition element MOD 1 ................................ Drawing 584090 MOD 2 .................................... MK 1 MOD 0


Diazodinitrophenol and potassium chlorate MOD 1 ................................. 45 milligrams MOD 2 ...............................................None

Lead styphnate MOD 1 ...............................................None MOD 2 .............................. 79.3 milligrams

Nitrocellulose MOD 1 ...............................................None MOD 2 ................................ 1.7 milligrams

Booster, class 4 black powder230 milligramsPrimer tube, class 2 black powder ......95 grams

A-5.2.6. Functioning Data.Primer resistance..................... 0.10 – 0.18 ohm

Recommended current Testing................................ < 50 milliamps

Firing......................................... > 10 amps Firing voltage .......................20 Vac or Vdc Electrostatic sensitivity ............8 x 105 ergs


A-5.2.7. Packing Data.LD 295793 ..........Inner pack, 7 primers per canDrawing 512849 .............................Outer pack,

4 cans per containerMIL-STD-1322/819A...................Palletization,



SW030-AA-MMO-010

A-45


A-5.3.1. General. Primers in this series were developed to provide a nonpercussion electric screw primer for use in 6-inch, 47 caliber ammuni-tion.

A-5.3.2. Description. All MODs consisted of a threaded stock, a brass plug, an ignition element, and a seamless steel primer tube into which was loaded a main charge of 87 grams of class 2 black powder (Figure A-55). The MOD 1 differed from the MOD 0 in that the sealing washer between the stock and plug had been eliminated. The MOD 1 was developed to improve the sealing against blowback gases. The ignition element in the MOD 1 had an initiator consisting of a double-arm bridgewire in diazodinitrophenol and potassium chlorate with a black powder booster charge. The ignition element in the MOD 2 was similar except that it used an initiating charge of lead styphnate and had been designated Ignition Element MK 1 MOD 0.


A-5.3.4. Physical Characteristics.Design data

Overall length ............................ 21.39 inches Boss diameter ............................ 1.187 inches Weight ......................................1.375 pounds Thread dimensions.................... 1.00-20NS-2 Primer tube data:

Length .................................... 20.25 inches Unvented length....................... 3.75 inches Vent diameter .............................0.218 inch No. of vents ............................................44Components

Stock MOD 0 ..............................................Brass MOD 1 ...............................................Steel MOD 2 ...............................................Steel

Plug .......................................................Brass Primer tube.............................................Steel Ignition element MOD 0 .............................Drawing 584090 MOD 1 .............................Drawing 584090 MOD 2 .................................MK 1 MOD 0


Diazodinitrophenol and potassium chlorate MOD 0 ................................. 45 milligrams MOD 1 ................................. 45 milligrams MOD 2 ............................................... None

Lead styphnate (MOD 2) ..... 79.3 milligrams Nitrocellulose (MOD 2) ......... 1.7 milligrams

Booster, class 4 black ........... 230 milligrams powder

Primer tube, class 2 black powder ..87 grams

Figure A-55 Primer MK 39 MODs (Electric), Cross-Sectional View

SW030-AA-MMO-010

A-46

A-5.3.6. Functioning Data.Primer resistance ..................... 0.10 – 0.18 ohmRecommended current

Testing....................................< 50 milliamps Firing............................................. > 10 amps Firing voltage.......................... 20 Vac or Vdc Electrostatic sensitivity............... 8 x 105 ergs


A-5.3.7. Packing Data. LD 255256.......... Inner pack, 7 primers per canDrawing 512849............................. Outer pack,

4 cans per containerMIL-STD-1322/819A .................. Palletization,



A-5.4.1. General. Primers in the MK 40 series were developed to provide a nonpercussion electric screw primer for use in the 6-inch, 47 caliber car-tridge case with a reduced charge round.

A-5.4.2. Description. MODs 1 and 2 (Figure A-56) were similar to the MK 39 MODs 1 and 2 except that the primer tubes had been shortened and the main charge had been reduced from 57 to 71 grams of class 2 black powder. All MODs con-sisted of a threaded stock, a brass plug, an ignition element, and a seamless steel primer tube into which a main charge was loaded. The MOD 1 dif-fered from the MOD 0 in that the sealing, washer between the stock and plug had been eliminated. The MOD 1 primer was developed to improve the sealing against blowback gases. The ignition ele-ment in the MOD 1 had an initiator consisting of a double-arm bridgewire in diazodinitrophenol and potassium chlorate with a booster charge of black powder. The ignition element in the MOD 2 was similar to that in the MOD 1 except that it used an initiating charge of lead styphnate and had been designated Ignition Element MK 1 MOD 0.

A-5.4.3. Interface. 6-inch, 47 caliber


Overall length............................ 16.89 inches Boss diameter ............................ 1.187 inches Weight ..................................... 1.100 pounds Thread dimensions ....................1.00-20NS-2 Primer tube data: Length.................................... 15.75 inches Unvented length ...................... 3.75 inches Vent diameter.............................0.218 inch No. of vents ............................................32Components

Stock MOD 0 ...............................................Brass MOD 1 ................................................Steel MOD 2 ................................................Steel

Plug .......................................................BrassPrimer tube .............................................Steel

Ignition element MOD 0 .............................Drawing 584090 MOD 1 .............................Drawing 584090 MOD 2 .................................MK 1 MOD 0

A-5.4.5. Explosive Data. Ignition charge

Diazodinitrophenol and potassium chlorateMOD 0................................. 45 milligrams

MOD 1................................. 45 milligrams MOD 2...............................................None

Lead styphnate (MOD 2) ..... 79.3 milligrams Nitrocellulose (MOD 2) ......... 1.7 milligrams Booster, class 4 black ........... 230 milligrams

powderPrimer tube, class 2 black powder ......71 grams

A-5.4.6. Functioning Data.Primer resistance..................... 0.10 – 0.18 ohmRecommended current

Testing ................................... < 50 milliamps Firing .............................................> 10 amps Firing voltage ..........................20 Vac or Vdc Electrostatic sensitivity ..........8 x 105 ergs at

400 micromicrofarads

SW030-AA-MMO-010

A-47

A-5.4.7. Packing Data.Drawing 5166059........... 200 primers per drum

A-5.5. Primer MK 35 MOD 1 (Case Combina-tion.

A-5.5.1. General. The MK 35 MOD 0 primer was a screw-type electric primer for use in sepa-rated ammunition developed for use in the MK 16 8-inch, 55 caliber gun. This primer was redesigned to provide percussion electric firing with a larger black powder charge and was designated MOD 1.

A-5.5.2. Description. This primer consisted of a threaded brass stock with a steel primer tube con-taining a class 2 black powder main charge (Figure A-57). The MOD 0, designed as an electric primer, was modified by replacing its plug, ignition element, and tube assembly with a combination percussion electric MK 20 MOD 0 primer. This modification to the stock, along with increasing the tube charge from 32.4 grams to approximately 87 grams of black powder, created the MOD 1.



Overall length ............................ 21.55 inches Boss diameter .............................. 1.60 inches Weight.........................................1.72 pounds Thread dimensions.................... 1.25-12NF-3 Primer tube Length .................................... 20.25 inches

Unvented length....................... 3.75 inches Vent diameter.............................0.218 inch No. of vents ............................................44Components

Stock......................................................Brass Plug ......................................................Brass Primer tube.............................................Steel

A-5.5.5. Explosive Data.Percussion .............Winchester cap No. 2-1/2

Electrical: guncotton ............... 12 milligrams Booster, class 6 black powder,

nitrocellulose........................ 18 milligramsThimble, class 4, black powder....1.94 gramsPrimer tube, class 2 black powder ..87 grams

A-5.5.6. Functioning Data.Primer resistance......................0.55 – 0.70 ohm

Recommended current Testing................................ < 50 milliamps Firing..........................................> 10 amps Firing voltage.......................20 Vac or Vdc Percussion sensitivity............16-ounce ball All fire......................................... 12 inches No fire ........................................... 3 inches

A-5.5.7. Packing Data.LD 255256..........Inner pack, 7 primers per canLD 168789.....Outer pack, 4 cans per containerMIL-STD-1322/819......................Palletization,



SW030-AA-MMO-010

A-48

A-6. TRACERS Tracers are devices designed to leave a visible

trail of smoke or flame from the base of projectiles during flight. Tracers permit observation of the trajectory of high-velocity projectiles, in darkness and in daylight, which would not otherwise be pos-sible. However, tracers have a number of disadvan-tages. When fired at night, they reveal the position of the firing ship. They consume critical war mate-rial. They occupy an appreciable portion of the rel-atively small space available in projectiles. In general, their use in fire control, except by the most skillful operators, is considered unsound because of misleading optical effects. Improvements in fire control have made the use of tracers in most pro-jectiles archaic.

A-6.1. Description. In general, a tracer consists of a steel body, a pyrotechnic train, and a closure disc of plastic or other suitable material. Standard tracer colors for antiaircraft projectiles are red and white; for armor-piercing and common projectiles, the tracer color is orange. The tracer mixture normally consists of an after-end starting mixture that may be easily ignited and an illuminant designed to burn during the flight of the projectile. The starting mixture is usually composed of barium peroxide and metal powders like magnesium or aluminum, which are pressed at about 60,000 pounds per square inch. Illuminants consist of oxidizing materials, such as barium nitrate and ammonium perchlorate; metal powders, such as magnesium and aluminum powder; and such inert materials as linseed oil and wax. The celluloid or metal cover disc seals the composition

in the tracer cavity and prevents the entry of moisture. Lead washers are placed between the shoulder on a tracer body and the corresponding seating surface in the base plug of the projectile. These washers prevent propellant gases from affecting the base fuze or explosive filler. All current Navy tracers are ignited by the burning of the propellant charge in the cartridge case or powder bag.

A-6.2. Identification and Marking. Navy trac-ers are identified principally by mark and MOD and by component lot number. The Naval Sea Sys-tems Command Headquarters assigns or controls the assignment of the number designations. Navy tracers are usually identified by lettering; normally they are not painted. The assignment of marks is restricted to the identification of tracers, which affect the physical or functional interchangeability, while MODs do not. MODs may affect certain functional parts of the basic tracer.

A-6.3. Classification. Tracers can be classified into three categories according to tracer location, method of assembly, and tactical features.

A-6.3.1. Tracer Location. Tracers are classified according to their locations with respect to the pro-jectile as follows:

a. Internal. This type of tracer (Figure A-58) fits inside the base of a projectile, inside the base fuze, if one is present. Its aft surface is flush with the base surface of the projectile. It is secured to the base fuze or to the base of the projectile by its threads.

Figure A-57 Primer MK 35 MOD 1 (Case Combination), Cross-Sectional View

SW030-AA-MMO-010

A-49

b. External. This type of tracer (Figure A-59) is attached by threads to the projectile but pro-trudes aft of the base surface of the projectile. It is used only in fixed ammunition.

A-6.3.2. Method of Assembly. Tracers are clas-sified further according to their method of assem-bly as follows:

a. Internal. These are tracers that are a part of the projectile or a part of the base fuze. The tracer composition is pressed into a cavity in the projectile or base fuze and is an integral part of the item.

b. Separate. These tracers are manufactured as a unit (Figure A-58 and Figure A-59) and are assembled as components in projectiles or base fuzes.

A-6.3.3. Tactical Features. Tracers are classi-fied according to their tactical features as follows:

a. Dark Ignition. In this type, the tracer does not become luminous for a certain distance from the gun muzzle. The starter mixture in this type usually has selenium, instead of a metal powder, mixed with the barium peroxide. This type of tracer does not produce the bright light of the regu-lar starting mixture and, therefore, does not blind gunners operating automatic weapons at night.

b. Self-Destruct. These tracers incorporate a black powder relay, which is ignited after the illu-minant has burned. The black powder burns through the length of its tube and initiates the explosive filler of the projectile, which is at the for-ward end of the tube. Self-destruction thus occurs at a determined range, unless the projectile first hits its target. Self-destruct tracers are presently loaded in much 40mm ammunition since the rela-tively short range of this ammunition makes it likely that rounds might fall and detonate on friendly ships or territory.

Figure A-58 Typical Internal Tracer, Cutaway View Figure A-59 Typical External

Tracer, Cutaway View

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A-50

A-6.4. Tracer MK 11.

A-6.4.1. General. Tracer MK 11 is an external tracer used in 40mm ammunition. There are three MODs of the MK 11. All of the MK 11 MODs contain the self-destruct feature of the black pow-der relay ignition charge. Self-destruction is initi-ated by the tracer at the end of burning. The MODs of Tracer MK 11 differ in the method used to secure the relay housing body. The body is threaded in the MOD 0, push-fitted in the MOD 2, and is an integral part of the tracer body in MOD 3.

A-6.4.2. Use.40mm AP-T, HE-SD, HEI-SD, HEIT-NSD,HET-SD

A-6.4.3. Physical Characteristics.Length............................................1.720 inches Diameter of head ................ 0.925 inch tapered

to 0.620 inchColor............................................................Red

A-6.4.4. Chemical Components.Starter mix

Luminous .......... Magnesium powder, bariumperoxide, aluminum powder

Dark ..............Selenium and barium peroxideIlluminant...... Magnesium powder, strontium

nitrate, ammonium perchlorate,charcoal, and wax

Relay ignition charge ...............Black powder

A-6.5. Tracer MK 14.

A-6.5.1. General. Tracer MK 14 is an external tracer used in 40mm ammunition. Tracer MK 14 is similar to Tracer MK 11 except that the end of the MK 14 is blanked off instead of having a relay housing.

A-6.5.2. Use.40mm projectiles

A-6.5.3. Physical Characteristics.Length............................................1.720 inchesDiameter of head ................. 0.925 inch tapered

to 0.620 inchColor............................................................Red

A-6.5.4. Chemical Components.Starter mix

Luminous........................Magnesium powderand barium peroxide

Dark.............. Selenium and barium peroxide Illuminant ......................Magnesium powder,

strontium nitrate, ammoniumperchlorate, charcoal, and wax

A-6.6. 3-Inch, 50 Caliber Ammunition.

A-6.6.1. Ammunition Interface. There are two gun mount interface categories of ammunition in the surface (2T) Navy inventory - slow fire (SF) and rapid fire (RF). Slow-fire gun mounts fire only ammunition assembled with percussion primers (MK 41). Rapid-fire gun mounts fire only ammu-nition assembled with electric primers (MK 42). The 3-inch, 50-caliber cartridges are used in the following gun mounts


SINCE THE SLOW FIRE POR-TION OF THE 3-INCH, 50 CALI-BER AMMUNITION IS PERCUSSION PRIMED; USE EXTREME CARE IN HANDLING TO AVOID STRIKING THE PRIMER AGAINST ANY OBJECTS.

The 3-inch, 50 caliber ammunition is a fixed round assembled with the primer and propellant contained in a cartridge case, which is permanently attached (crimped) to a projectile. Figure A-60shows the 3-inch, 50 caliber cartridge. The ammu-nition external configuration, weight, and ballistics of all types of service cartridges are basically the

Slow-FireAmmunition Rapid-Fire Ammunition

MK 22 Single Gun Mount MK 33 Twin Gun Mount

MK 26 Single Gun Mount MK 34 Single Gun Mount

MK 27 Twin Gun Mount

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A-51

same. The projectile and its fuzing constitutes the other major differences in this ammunition. Table A-11 presents the ammunition characteristics.

A-6.6.2.1. Projectiles. The choice of projectiles for 3-inch, 50 caliber ammunition varied widely and provided the largest inventory of all surface Navy guns. See Table A-11.

A-6.6.2.2. High Explosive (HE). HE projectiles are general purpose projectiles (Figure A-61), used primarily to provide blast and fragmentation. The projectile can be fuzed with either impact or prox-imity fuzing. The principal variations in these pro-jectiles are described below.

Figure A-60 3-Inch, 50-Caliber Ammunition Data

Table A-11 3-Inch, 50-Caliber Ammunition Data

Cartridge

Projectile Propulsion

Weight(lb.)

(Approx.)DODIC

BodyExplosive

Filler NozeFuze

AD Fuze or

Booster

Base Fuze or Tracer Hole Plug

Cartridge Case

MK 7 BrassMK 9 Steel

Primer1

RF or SF

Propellant

Type2 Wt. (lb.)(Approx.)

HE-VT-SD MK 33 A-3 MK 72/2,6,8 MK 44 – MK 7 or 9 RF SPDF 4.1 24.4 C136

NSD MK 33 A-3 MK 72/3,7,9 MK 44 – MK 7 or 9 RF SPDF 4.1 24.4 C137

SD MK 33 A-3 MK 72/2,4,6,8 MK 44 – MK 7 or 9 RF SPDN 4.1 24.4 C140

NSD MK 33 A-3 MK 72/1 MK 44 – MK 7 or 9 RF SPDN 4.1 24.4 C141

NSD MK 33 A-3 MK 72/11,13 bstr – MK 7 or 9 RF SPDF 4.1 24.4 C150

NSD MK 33 A-3 MK 72/11,13 bstr – MK 7 or 9 RF SPDN 4.1 24.4 C151

SD MK 33 A-3 MK 72/10,12 bstr – MK 7 or 9 RF SPDF 4.1 24.4 C152

SD MK 33 A-3 MK 72/10,12 bstr – MK 7 or 9 RF SPDN 4.1 24.4 C153

NSD MK 33 A-3 MK 72/17 bstr – MK 7 or 9 RF SPDF 4.1 24.4 C151

SD MK 31 A-3 MK 72/2,6,8 MK 44 – MK 7 or 9 SF SPDN 4.1 24.6 C207

SD MK 31 A-3 MK 72/10 bstr – MK 7 or 9 SF SPDN 4.1 24.6 C207

NSD MK 31 A-3 MK 72/3,5,7,9 MK 44 – MK 7 or 9 SF SPDN 4.1 24.6 C208

NSD MK 31 A-3 MK 72/11,13 bstr – MK 7 or 9 SF SPDN 4.1 24.6 C208

SD MK 31 A-3 MK 72/2,6,8 MK 44 – MK 7 or 9 SF SPDF 4.1 24.6 C355

SD MK 31 A-3 MK 72/10,12 bstr – MK 7 or 9 SF SPDF 4.1 24.6 C355

NSD MK 31 A-3 MK 72/3,7,9 MK 44 – MK 7 or 9 SF SPDF 4.1 24.6 C356

SW030-AA-MMO-010

A-52

NSD MK 31 A-3 MK 72/11,13 bstr – MK 7 or 9 SF SPDF 4.1 24.6 C356

HE-IR MK 33 A-3 MK 92 bstr – MK 7 or 9 RF SPDN 4.1 24.8 C306

MK 175/0 MK 33 A-3 MK 92 bstr – MK 7 or 9 RF SPDN 4.1 24.8 C306

MK 175/1 MK 33 A-3 MK 404 – – MK 7 or 9 RF SPDN 4.1 24.8 C306

MK 33 A-3 MK 92/0,1 bstr – MK 7 or 9 RF SPDF 4.1 24.8 C307

MK 31 A-3 MK 92/1 bstr – MK 7 or 9 SF SPDN 4.1 24.8 C321

MK 31 A-3 MK 92/1 bstr – MK 7 or 9 SF SPDF 4.1 24.8 C322

HE-PD MK 27 TNT MK 30/5 MK 54 Plug MK 7 or 9 SF SPDN 4.1 24.8 C349

HC MK 27 TNT MK 30 PD MK 54 Plug MK 7 or 9 SF SPDN 4.1 24.5 C218

MK 27 TNT MK 30 PD MK 54 MK 7 or 9 SF SPDF 4.1 24.5 C296

MK 27 TNT MK 30 PD MK 54 Plug MK 7 or 9 RF SPDF 4.1 24.5 C347

MK 33 A-3 MK 30 PD MK 54 – MK 7 or 9 RF SPDF 4.1 24.4 C347

MK 27 TNT MK 30 PD MK 54 Plug MK 7 or 9 RF SPDN 4.1 24.5 C348

MK 33 A-3 MK 30 PD MK 54 – MK 7 or 9 RF SPDN 4.1 24.4 C348

AA MK 27 TNT MK 51 MT MK 54 Plug MK 7 or 9 SF SPDN 4.1 24.5 C299

MK 27 TNT MK 51 MT MK 54 Plug MK 7 or 9 SF SPDF 4.1 24.5 C302

AP MK 29 Expl-D – – M663 MK 7 or 9 RF SPDF 4.1 24.8 C143

MK 29 Expl-D – – M663 MK 7 or 9 SF SPDN 4.1 24.8 C212

MK 29 Expl-D – – M663 MK 7 or 9 SF SPDF 4.1 24.8 C215

ILLUM MK 25 MK 4 or 12 MK 51 MT – – MK 7 or 9 SF SPDF 4.1 24.8 C305

MK 25 MK 4 or 12 MK 51 MT – – MK 7 or 9 SF SPDF 4.1 24.8 C305

TP-VT-SD MK 31 CBU-Gray MK 72/2,4,6,8 MK 44 – MK 7 or 9 RF SPDN 4.1 24.6 C162

(NON- MK 33 CBU-Gray MK 72/10,12 bstr – MK 7 or 9 RF SPDN 4.1 24.4 C162

FRAG) NSD

MK 31 CBU-Gray MK 72/1,3,5,7,9

MK 44 – MK 7 or 9 RF SPDN 4.1 24.6 C164

MK 33 CBU-Gray MK 72/11,13 bstr - MK 7 or 9 RF SPDN 4.1 24.4 C164

SD MK 31 CBU-Gray MK 72/2,4,6,8 MK 44 – MK 7 or 9 SF SPDN 4.1 24.6 C319

SD MK 31 CBU-Gray MK 72/10,12 bstr – MK 7 or 9 SF SPDN 4.1 24.6 C319

NSD MK 31 CBU-Gray MK 72/1,3,5,7,9

MK 44 – MK 7 or 9 SF SPDN 4.1 24.6 C320

NSD MK 31 CBU-Gray MK 72/11,13 bstr – MK 7 or 9 SF SPDN 4.1 24.6 C320

SD MK 36 CBU-Red/Yellow or

Blue

MK 72/10,12 bstr – MK 7 or 9 RF SPDN 4.1 24.4 C373

Table A-11 3-Inch, 50-Caliber Ammunition Data (Continued)

Cartridge


Weight(lb.)

(Approx.)DODIC

BodyExplosive

Filler NozeFuze

AD Fuze or

Booster


Cartridge Case


Primer1

RF or SF

Propellant


SW030-AA-MMO-010

A-53

A-6.6.2.2.1. High Explosive, Variable Time (Self-Destructive and Non-Self-Destructive) [HE-VT (SD and NSD)]. This projectile is designed for use against targets that are vulnerable to airburst. The thin-walled, hollow steel projectile body is threaded at the nose and fitted with a VT-RF proximity fuze. A self-destructive feature is

incorporated into the MK 72 MODs 2, 4, 6, 8, 10, and 12 nose fuzes, while this self-destructive fea-ture is omitted in the MK 72 MODs 3, 5, 7, 9, 11, and 13. An AD fuze or a fuze booster is installed to supplement the nose fuze (MK 72). There are two projectile bodies used in this series of projec-tiles – the MK 31 and the MK 33. Both projectile bodies are explosive loaded with Composition A-3, and both have a flat and solid base.

A-6.6.2.2.2. High Explosive, Infrared (HE-IR). The HE-IR projectile is designed exclusively for use against hot airborne targets. This projectile is described above, with the difference being nose fuzing (infrared).

A-6.6.2.2.3. High Explosive, Point Detonating (HE-PD). The HE-PD projectile is designed for use against targets that are vulnerable to impact burst. The thin-walled, hollow steel projectile (MK 27) body is threaded at the nose and fitted

NSD MK 36 CBU-Red/Yellow or

Blue

MK 72/11,13 bstr – MK 7 or 9 RF SPDN 4.1 24.4 C375

BL-P MK 177/1

MK 27 Inert Dummy – Plug MK 7 or 9 RF SPDN 4.1 24.5 C178

MK 188/0 MK 27 Inert Dummy – Plug MK 7 or 9 RF SPDF 4.1 24.5 C179

MK 189/0 MK 27 Inert Dummy – Plug MK 7 or 9 SF SPDN 4.1 24.5 C338

MK 185/0 MK 27 Inert Dummy – Plug MK 7 or 9 SF SPDF 4.1 24.5 C341

Clearing Charge

– – – – – MK 7 or 9 SF SPDF 3.8 9.5 C184

– – – – – MK 7 or 9 RF SPDF 3.8 9.5 C185

MK 7 or 9 SF Black Powder

- 7.4 C139

Saluting Charge

– – – – – MK 7 or 9 SF Black Powder

2.0 7.4 C183

1 - RF, rapid fire, Primer MK 42 (Electric): SF, slow fire, Primer MK 14 or 41 (Percussion).

2 - Flashless cartridges loaded with either SPDF or SPCF propellant. Nonflashless cartridges loaded with either SPDN, SPD, or SPDB propellant.

3 - Fuze M66 is not boresafe and should not be used except in a combat emergency.

Table A-11 3-Inch, 50-Caliber Ammunition Data (Continued)

Cartridge


Weight(lb.)

(Approx.)DODIC

BodyExplosive

Filler NozeFuze

AD Fuze or

Booster


Cartridge Case


Primer1

RF or SF

Propellant


Figure A-61 3-Inch, 50-Caliber, High Explosive Projectile

SW030-AA-MMO-010

A-54

with a PD fuze, supplemented by an AD fuze. The base tracer hole is plugged. The projectile body cavity is explosive loaded with approximately 0.74 pound of TNT.

A-6.6.2.3. High Capacity (HC). The HC pro-jectile (Figure A-62) is designed for use against unarmored surface targets, shore installations, per-sonnel, or aircraft. There are two projectile config-urations used for the high capacity cartridge, the MK 27 and the MK 33. Both projectile bodies are threaded to receive nose fuzing, but the base of the MK 27 projectile body has a protruding boss threaded internally, which is designed to receive a tracer but is plugged on the current configuration. The base of the MK 33 projectile body is solid and flat. The hollow steel projectile body is assembled (360-degree crimp) to only percussion primed pro-pelling charges and is issued for use with hand-rammed, slow-fire gun mounts because rapid fire gun mounts have no fuze setters.

A-6.6.2.4. Antiaircraft (AA). This thin-walled, low-fragmentation steel projectile (Figure A-63) is configured for use against surface targets that are vulnerable to airburst. The projectile body cavity is explosive loaded with approximately 0.74 pound of TNT and is fitted with an MT fuze (MK 51 or MK 342) and an AD fuze (MK 54). Some AA pro-jectiles have been reworked, and the MK 54 MOD 0 fuzes were replaced; therefore, the mark-ings on the fuzes may be different from the mark-ings on the sealing cup assemblies. This projectile is assembled (360-degree crimp) to only percus-

sion primed propelling charges and is issued for use with hand-rammed, slow fire gun mounts because rapid fire gun mounts have no fuze setters.

A-6.6.2.5. Armor Piercing (AP).

ALL 3-INCH, 50 CALIBER ARMOR PIERCING PROJEC-TILES ASSEMBLED WITH BASE DETONATING FUZE M66 ARE RESTRICTED TO COMBAT EMERGENCY USE ONLY. THE M66 FUZE IS NOT BORESAFE AND SHOULD BE HANDLED CAREFULLY.

The 3-inch, 50 caliber AP projectile (Figure A-64) is developed for use against armored targets by using kinetic energy of impact. Once inside the target, the 0.016-second delayed-action base fuze functions to detonate the 0.14 pound of Explosive D filler. The projectile is comprised of a forged steel body, an AP cap, a screw-on aluminum wind-shield, and a screw-in base plug fitted with a base detonating fuze. M66 fuzes assembled in current AP stock are known to be of low reliability; there-fore, high dud rates are expected, but are not to be reported as malfunctions.

Figure A-62 3-Inch, 50-Caliber, High Capacity Projectile, MK 33

Figure A-63 3-Inch, 50-Caliber, Antiaircraft High Capacity Projectile, MK 27

SW030-AA-MMO-010

A-55

A-6.6.2.6. Illuminating (ILLUM). The ILLUM projectile (Figure A-65) is designed to cast (sus-pend) a bright light for targets or areas for tactical and training purposes. The MK 25 projectile is fit-ted with an MT fuze (MK 51 or MK 342). The projectile has a MK 4 or MK 12 illuminating load and a small (10.6 grams) black powder explosive charge sealed within the projectile body by a base plate. When the fuze functions, it ignites the black powder, which shears the base plate shear pins and expels the illuminating load. The illuminating composition is a powdered magnesium mixed with an oxidizer that burns for approximately 25 sec-onds with a candlepower of 120,000 (MK 4) or 250,000 lumens (MK 12).

A-6.6.2.7. Nonfragmenting Target Practice (TP). The nonfragmenting TP projectile (Figure A-66) is designed for use in antiaircraft target prac-tice, particularly against expensive drone targets, for observing the firing results, frequently without loss of the drone. A standard projectile body is filled with inert material around the color burst unit to obtain the desired weight. The nose of the pro-jectile is fitted with a VT-RF proximity fuze, sup-plemented either by a fuze booster or an AD fuze. A self-destruct capability is incorporated in the MK 72 MODs 2, 4, 6, 8, 10, and 12 nose fuzes (C162, C319, and C373 cartridge). The self-destruct feature is omitted in the MK 72 MODs 3, 5, 7, 9, 11, and 13 nose fuzes (C164, C320, and C375 cartridge). A fuze cavity liner separates the fuze from the color burst unit and the inert filler. The color burst is ignited through the action of the nose fuze and the black powder pellets. The base of the projectile is solid.

A-6.6.2.8. Blind Loaded and Plugged/Tracer (BL-P/T). The standard thin-walled projectile (MK 27) is filled with inert material to bring it within the weight tolerance of the service projec-tile. The nose of the projectile is fitted with a dummy nose plug, while the base is plugged flush. Tracers are no longer assembled in new produc-tion. These cartridges are for target practice, rang-ing, and proving ground test.

A-6.6.3. Propelling Charge. The 3-inch, 50 caliber propelling charge (Figure A-67) consists of the following: a MK 7 brass or a MK 9 steel car-tridge case of a necked-down mouth design, a MK 14 or MK 41 percussion (SF) or a MK 42 elec-tric (RF) primer, and either a nonflashless propel-lant (SPDN) or a flashless propellant (SPDF or



Figure A-66 3-Inch, 50-Caliber Nonfragmenting, Target Practice Projectile

SW030-AA-MMO-010

A-56

SPCG). A cardboard wad and a distance piece are placed on top of the propellant, and a lead foil (decoppering agent) is fitted inside the triangular distance piece. The amount of lead foil for each propelling charge is 30 ± 3 grams for flashless pro-pellant; except for the ILLUM projectile, which is 15 ± 2 grams; and 45 ± 5 grams for the nonflash-less propellant. The distance piece is cut to the required length as governed by the propellant pro-duction packing depth (PPD).

NOTECartridges with percussion primed pro-pelling charges are only for use in slow fire gun mounts, while electric primed propelling charges are for rapid fire gun mounts.

A-6.6.4. Clearing Charge. The clearing charge uses components common to the standard 3-inch, 50 caliber propelling charge assembly, with the major difference being that the MK 7 or MK 9 car-tridge case is shortened by approximately 5.0 inches. Clearing charges are used to clear guns by firing projectiles after propelling charge misfires or a loading jam occurs. The shortened cartridge case is loaded with 3.8 pounds of flashless propellant and is primed with either a MK 41 percussion primer (C184 charge) or a MK 42 electric primer (C185 charge). The mouth of the cartridge case is closed with an inverted pyralin wad, topped with a cork closure plug. Both wad and closure plug are cemented to the cartridge case.

A-6.6.5. Blank Saluting Charge. These charges are used to render salutes and other honors. Since no projectile is involved in such firings, the charge consists of a shortened (approximately 5.0 inches) MK 7 or MK 9 cartridge case, loaded with

black powder, a closure plug, and a primer. There are two 3-inch, 50 caliber saluting charges in the inventory, the major difference being the amount of black powder charge. The C139 (SF) charge is loaded with 1.0 pound of black powder (bagged), and the C183 (SF) charge is loaded with 2.0 pounds of black powder (bagged).

A-6.6.6. Dummy Cartridge. Dummy car-tridges (Figure A-68) were used to exercise gun crews in loading and for testing ammunition hoists and other ammunition handling equipment. They were designed to simulate a loaded service car-tridge, represented as to size, form, and weight.

A-6.7. Packing. The ammunition was handled and shipped according to OP 4 and OP 5. The ammunition is painted, marked, and lettered according to WS 18792. The packaging require-ments are according to OR 68/41 (for tanking) and MIL-STD-1323/1 (for palletizing).

A-6.8. Ballistic Data. The ballistic data for the 3-inch, 50 caliber are as follows:

A-6.8.1. Average Muzzle Velocity. The aver-age muzzle velocity is 2,700 feet per second.

A-6.8.2. Maximum Range. The maximum range is 14,200 yards.

A-7. BLACK POWDER

A-7.1. Description. Black powder is a propel-lant, though its use in the Navy is limited to ignit-ers, expelling charges, a delay element and sometimes a magazine element in fuzes, a noise-maker in saluting charges, and a propellant for impulse charges. In its primary function as an igniter material, it is loaded into primer tubes for cased charges. Its characteristic of having a burn rate which is nearly independent of pressure makes it a good match for these uses.

Figure A-67 3-Inch, 50-Caliber Propelling Charge

Figure A-68 3-Inch, 50-Caliber Dummy Cartridge

SW030-AA-MMO-010

A-57/(A-58 blank)

A-7.1.1. Classes of Black Powder. The appear-ance of black powder is adequately described by its name. The granulation of the powder is varied to accomplish the purpose for which it may be employed. Generally, the finer the granulation, the more rapidly is pressure developed in the combus-tion. Various granulations of black powder are used in loading gun ammunition components such as fuzes, saluting charges, primers, and expelling charges. Formerly designated by grades, granula-tion size is now designated by class (determined by a process using U.S. standard sieves) as follows:

A-7.2. Grain Geometry. The burning character-istics of a propellant formulation, the pressure at which it is burning, and the surface area history of a granulation are what determine the rate at which gas is produced. The burning characteristics of a propellant are determined by the formulation, and the manner in which the propellant is processed, and the pressure is a function of the gun parame-ters, which leaves the surface area as the only fac-tor through which we can control the pressure history in the gun. For a given weight of propel-lant, large grains will have a smaller total surface area, therefore less surface burning and generating gas. The pressure rise from large grains will be slower than for small grains, and likewise grains with more perforations will yield faster pressure rises than those with few perforations. The size

and shape of the grain must be carefully matched to the gun performance. If the grains are too small and so generate gas too quickly, overpressurizing the gun can result. If the grains are too large, they may not burn out completely before the projectile exits the muzzle and so yield less than optimal per-formance. Grain size is typically discussed in terms of the web. The web is the distance between two adjacent burning surfaces and is illustrated for single- and seven-perforated grains in Figure A-69. Table A-12 gives examples of some typical grain sizes for various gun systems.

Figure A-69 Propellant Grain Web Locations

Table A-12 Relative Grain Sizes by Gun Caliber

Gun Size Number of Perforations

GrainLength (in.)

Grain Diameter (in.)

Perforation Diameter (in.) Web Thickness (in.)

3-in, 50-cal 7 0.50 0.20 0.016 0.033

5-in, 38-cal 7 0.70 0.30 0.031 0.051

6-in, 47-cal 7 1.00 0.40 0.046 0.074

8-in, 55-cal 7 1.20 0.50 0.054 0.089

16-in, 45-cal 7 1.97 0.85 0.06 0.170

16-in, 50-cal 7 2.00 1.00 0.060 0.190

SW030-AA-MMO-010

B-1

APPENDIX B

NOSE FUZE REMOVAL/REPLACEMENT, AND SETTING

B-1. FUZE SETTERS AND WRENCHES This section describes the fuze wrenches and

time fuze setters used with Navy gun ammunition.

B-1.1. Fuze Wrenches. Fuze wrenches and their applications are given in Table B-1. The vise grip wrench, shown in Figure B-1, is used to remove

and replace nose fuzes in projectiles having nose fuze adapters. Figure B-2 shows wrenches used for the removal and replacement of waterproof pro-tective caps and plastic windshields used on pro-jectiles.

Figure B-1 Use of Vise Grip Nose Fuze Adapter Wrench on Projectile

SW030-AA-MMO-010

B-2

B-1.2. Fuze Setters. A list of setting tools and their application is given in Table B-1. The MK 342 MT fuze and the MK 393 MT/PD fuze are normally set by the automatic fuze setter located in the 5-inch, 54 caliber gun mount. The M732 CVT fuze may also be set by the 5-inch, 54 caliber auto-matic fuze setter if the fire control has received the appropriate ORDALT; otherwise, it is set by hand. MK 349 MT fuze and MK 403 MT/PD fuze are normally set by the automatic fuze setter located in the 5-inch, 38 caliber gun mount. The setting tools are used to reset the fuze to the “safe” or PD posi-tion if the rounds are not fired or to reset the fuzes if the automatic fuze setters are not operating. The MK 51 MT fuze, the M513A2, M514A1, M728, and M732 CVT fuzes are always set by hand with the appropriate fuze wrench (see Table B-1 and Figure B-3 and Figure B-4). M724, M724 with booster, and MK 423 MOD 0 ET fuzes are always set electronically by the portable M36 fuze setter. A description of the fuze setter and instructions for its use are included here.

B-1.3. Fuze Setter M36. The M36 fuze setter is used to set M724 and MK 423 MOD 0 electronic time fuzes to function at a specified time or in PD mode. A fuze may be interrogated by the setter to determine what mode and time was set previously.

B-1.3.1. Description. Table B-2 gives the phys-ical characteristics of the fuze setter and con-tainer. The fuze setter is packaged in a metal carrying case with a remote probe, a battery charge cable, and a bristle brush (Figure B-5). The major components of the fuze setter (Figure B-6) are the mode and time setting toggle switches, the fuze setting display, the remote probe connector, and the battery charge connector. A push button, located on the top of the setter, may be used to light the set-ting switches when needed. Operating instructions are located on the front of the setter directly below the fuze setting display. The nomenclature and serial number of the fuze setter and battery recharging instructions are located on the back of the setter.

Figure B-2 Fuze Wrenches

Figure B-3 Typical Auxiliary Fuze Setting Wrench

Figure B-4 Fuze Setter M27

SW030-AA-MMO-010

B-3

B-1.3.1.1. Mode and Time Switches. The MODE and TIME SECONDS switches (Figure B-7) can be set by toggling either forward or back-ward to the following positions:

MODE: OFF, TI, TI, ?, PD

TIME SECONDS:

Hundreds 0 1

Tens 0 1 2 3 4 5 6 7 8 9

Units 0 1 2 3 4 5 6 7 8 9

Tenths 0 1 2 3 4 5 6 7 8 9Either of the two time-initialized (TI) switch

positions permits the setter to set the fuze to func-tion at a desired time (0.2 to 199.9 seconds) in 0.1-second setting increments. Switch position PD per-mits the setter to set the fuze to a point detonation mode. In the ? position, the setter interrogates the fuze and displays the previously set function (P) or the memorized time setting to the nearest 0.01 sec-ond.

Table B-1 Fuze Wrenches and Setters Used with Navy Gun Ammunition

Identification NAVSEASYSCOMDrawing No. NSN Function Used with -

(Ammunition/Fuze)

Fuze wrenches:

Vise grip 5120-00-104-1819 Remove/replace nose fuze 5-inch, 38 caliber;5-inch, 54 caliber

Cover wrench (Same as Spanner MK 2)

245747-3 5120-00-026-8444 Remove/replace waterproof protective cap MK 1

5-inch, 38 caliber

Spanner MK 2 301042 6105-00-051-2492 Remove/replace waterproof protective cap MK 1

5-inch, 38 caliber

Spanner MK 3 437781 1520-00-382-6918 Remove/replace waterproof protective cap MK 4

5-inch, 54 caliber

Windshield 249306 None assigned Remove/replace windshield 5-inch, 38 caliber

Fuze setter:

Auxiliary fuze setting wrench

245748-2 (Replaced by

510361-1)

1020-00-382-6910 Set/reset fuze time MK 25, MK 51, MK 342, MK 393, M513, M514, M728, M732

Auxiliary fuze setting wrench

245748-4 1020-00-382-6911 Set/reset fuze time MK 349, MK 50, MK 61, MK 403

Auxiliary fuzesetting wrench

510361-1 5120-00-623-0194 Set/reset fuze time MK 25, MK 51, MK 342, MK 393, M513, M514, M728, M732

M27 (T40) 7647761 (Army) 1290-00-764-7761 Set/reset fuze time MK 25, MK 51, MK 342, MK 393, M513, M514, M728, M732

M36 11711372 (Army) 1290-01-038-2035 Set/reset fuze time M724, M724 boost-ered

SW030-AA-MMO-010

B-4

Figure B-5 Fuze Setter M36

SW030-AA-MMO-010

B-5

Figure B-6 Fuze Setter M36 Major Components

SW030-AA-MMO-010

B-6

B-1.3.1.2. Fuze Setting Display. Upon contact of the fuze setter probe with the fuze nose, the desired mode and time setting are set automatically into the fuze memory and are displayed in the FUZE SETTING DISPLAY:

B-1.3.2. Operation. A fuze is set by contact of either the fuze setter probe or the remote probe with the bullseye rings of fuze nose. Feedback from the fuze to the fuze setter confirms that the set time is memorized within a tolerance of +0.08, -0.06 second by displaying the time toggled into the setter. If the memorized time is not within the tol-erance specified above, the setter displays the error code E. When E is displayed or if the fuze is removed from the setter before completion of the timing cycle, the setter automatically sets the fuze in the PD mode. A fuze can be reset repeatedly without damage and retains the last setting indefi-nitely. Set fuzes according to the following:

a. Toggle MODE switch to desired setting as follows:

(1) TI – to set desired time function(2) PD – to set point detonating function(3) ? – to interrogate fuze without chang-

ing setting.

b. If TI mode is selected, enter desired time (0.2 to 199.9 seconds) by toggling TIME SEC-ONDS switches.

c. Contact fuze nose with setter probe or remote probe, and read display.

d. If display matches switch settings, remove probe from fuze. Fuzed projectile is ready for fir-ing.

e. If E is displayed, repeat procedure two times.

f. If E display repeats, repeat procedure with another fuze setter.

g. If E is displayed with second fuze setter, do not use fuze.

Figure B-7 MODE Switch TI and PD Positions

Table B-2 Fuze Setter M36 Physical Characteristics

Characteristic Measure

Fuze Setter:

Weight 10.0 lbs.

Length 8.7 in.

Width 3.5 in.

Height 8.7 in.

Container:

Dimensions 12 x 13.36 x 6.09 in.

Weight (1 setter/container) 25 lbs. 4 oz.

Mode Display Indication

TI Matching switch setting indicates properly set time function if within tolerances

PD P indicates properly set PD function

? 1. Memorized set time function to nearest 0.01 second (set time +0.08, -0.06)

2. P indicates fuze previously set for PD

All 1. E indicates operating error (e.g., trying to set less than 0.2 seconds), bad fuze, or malfunction of fuze setter

2. L indicates low battery voltage

Mode Display Indication

SW030-AA-MMO-010

B-7/(B-8 blank)

h. If second fuze setter displays correctly, first fuze setter is malfunctioning. See Paragraph B-1.3.3.

i. If L is displayed, recharge battery as soon as possible. See Paragraph B-1.3.3.

B-1.3.3. Maintenance. The M36 fuze setter was designed to provide reliable service with mini-mum maintenance. Only periodic cleaning of the fuze setter contacts and charging of the battery are needed.

B-1.3.3.1. Cleaning. If when setting a fuze the error code E is displayed, check the bullseye rings on the fuze nose and the contacts of the fuze setter probe or remote probe for dirt and moisture. Clean rings and contacts with the bristle brush. If the set-ter still displays E, return fuze setter to depot.

B-1.3.3.2. Battery Charging. When L is dis-played on the fuze setting display, the battery is running down and should be charged as soon as possible. It is possible to set about 100 fuzes after the L displays and before the setter stops. A fully charged battery should set 4,000 fuzes at room temperature. To charge the battery, connect the charge cable to the fuze setter BATTERY CHARGE connector (Figure B-6). Attach the other end of the cable to a 20 to 28 dc volt power

source. The time required to fully charge the bat-tery depends on the temperature. Table B-3 gives the times required over a temperature range of -40 to 145 degrees F.

Table B-3 Time Required to Charge Fuze Setter Battery

Temperature (°F)

Temperature (°C)

Charge Time (hr.)

-401 -40.01 168

-201 -28.91 80

-10 -23.3 67

0 -17.8 41

20 -6.7 19

40 4.4 10

60 15.6 7

80 26.7 7

100 37.8 7

120 48.9 7

145 62.8 7

1 Charging at these temperatures may not adequately recharge the battery; however, no damage to the setter or the battery will occur.

SW030-AA-MMO-010

C-1

APPENDIX C

AMMUNITION AND FUZE DATA SHEETS

INDEX OF FIGURES

M732 Controlled Variable Time - Radio Frequency Proximity Fuze C-2

M732 Controlled Variable Time - Radio Frequency C-3

MK 30 MOD 5 Point Detonating Fuze C-4

MK 67 MOD 3 Propelling Charge C-5

MK 80 All Up Round C-7











MK 393 MOD 0 Mechanical Time/Point Detonating Fuze C-18

MK 399 MOD 1 Point Detonating/Delay Fuze C-19

MK 404 MOD 2 Variable Time Infrared (VT-IR) C-20

MK 407 MOD 1 Point Detonating/Delay Fuze C-22

MK 418 MOD 0 Variable Time - Radio Frequency Proximity Fuze C-24

MK 419 MOD 0 Multi-Function Fuze (MFF) C-26

SW030-AA-MMO-010

C-2

Figure C-1 M732 Controlled Variable Time - Radio Frequency Proximity Fuze

SW030-AA-MMO-010

C-3

Figure C-2 M732 Controlled Variable Time - Radio Frequency

SW030-AA-MMO-010

C-4

Figure C-3 MK 30 MOD 5 Point Detonating Fuze

SW030-AA-MMO-010

C-5

Figure C-4 MK 67 MOD 3 Propelling Charge

SW030-AA-MMO-010

C-6

Figure C-4 MK 67 MOD 3 Propelling Charge (Continued)

SW030-AA-MMO-010

C-7

Figure C-5 MK 80 All Up Round

PM4

Approved for public release, distribution is unlimited.

MK 80 ALL UP ROUND

High Explosive - Point Detonating (HE-PD)

PURPOSE: This general purpose projectile is used primarily for blast and

fragmentation effects against surface targets vulnerable to an impact burst.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body

loaded with explosive Composition A-3. A cavity liner separates the Auxiliary

Detonating (AD) fuze from the main charge. The base of the projectile is solid with a

½-caliber boattail and a copper rotating band to provide spin and obturation. The

projectile is fitted with a Point Detonating (PD) and an Auxiliary Detonation (AD) fuze.

CONFIGURATION

OPERATIONAL DESCRIPTION: Prior to placing the projectile in the loading

hoist of the gun, a setting screw on the MK 30-5 nose fuze must be set to the ON

position to permit arming. When the projectile is fired, the fuze is armed by

centrifugal force resulting from projectile spin. The projectile detonates instantly

upon impact. A MK 395 AD fuze is used for additional safety, providing 360 feet safe

separation distance, and to effectively detonate the main charge. The MK 30-5 nose

fuze also features a rain baffle assembly to prevent it from functioning early during

firings in heavy rainfall.

PERFORMANCE

CHARACTERISTICS

PHYSICAL DATA

Length: 26 in. (66 cm)

Weight: 67.63 lbs (30.68 kg)

Material: AISI 1050 Steel

5”/54 with MK 67 5”/62 with MK 67

Range 25,294 yds*

(23,129 m)

25,875 yds**

(23,660 m)

Service

Pressure

53.1 ksi

(366.1 MPa)

53.1 ksi

(366.1 MPa)

Muzzle

Velocity

2,650 ft/sec

(808 m/sec)

2,700 ft/sec

(823 m/sec)

Nose

MK 30-5AD

MK 395

MK 80-0 MK 64

Pressed

Comp A-3

(RDX)

FUZEASSEMBLY BODYLOAD NATIONAL STOCK

NUMBER

1320-01-007-0821

*Range Table - SW323-AB-ORD-020, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge, EDC 1.02

**Range Table - unpublished

Department of Defense Identification Code (DODIC) D330

U. S. NAVY 5-INCH GUN AMMUNITION FACT SHEET

SW030-AA-MMO-010

C-8


PM4

MK 91 ALL UP ROUND

Illuminating - Mechanical Time (ILLUM-MT)

PURPOSE: This round provides area illumination by a parachute-suspended flare

that provides 72 seconds of light intensity at 723,000 candlepower for multiple missions.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body

loaded with a parachute-suspended candle for surface illumination. The base of the

projectile is a press-fit plug. The body has a cylindrical base and two copper rotating

bands to provide spin and obturation. The projectile is fitted with a Mechanical Time

(MT) fuze and an Auxiliary Detonating (AD) fuze.

CONFIGURATION

OPERATIONAL DESCRIPTION: The fuze setting is calculated by the fire

control to function at an altitude of 1050 feet (320 meters) over the target area. When

the MT and AD fuzes function, the AD fuze ignites the black powder, which expels the

projectile illuminating load. A ram-air inflatable decelerator then deploys providing

enough drag to slow the spin rate and velocity of the illuminating load to manageable

levels for the main parachute. The burning flare separates the decelerator and the

parachute is allowed to deploy. Full deployment occurs several seconds after the first

visible light from the candle.

PERFORMANCE

CHARACTERISTICS

PHYSICAL DATA

Length: 26.09 in. (66.3 cm)

Weight: 63.92 lbs (28.99 kg)

Material: AISI 1050 Steel

5”/54 with MK 67 5”/62 with MK 67

Range 18,085 yds*

(16,537 m)

18,341 yds**

(16,771 m)

Service

Pressure

53.1 ksi

(366.1 MPa)

53.1 ksi

(366.1 MPa)

Muzzle

Velocity

2,700 ft/sec

(823 m/sec)

2,750 ft/sec

(838 m/sec)

Nose

MK 342AD

MK 396

MK 91-0 MK 48-1Illum

MK 18

FUZEASSEMBLY BODYLOAD NATIONAL STOCK

NUMBER

1320-01-096-9465

*Range Table - SW323-EO-MMO-010, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge

**Range Table - unpublished



SW030-AA-MMO-010

C-9


PM4

MK 92 ALL UP ROUNDBlind Loaded and Plugged (BL-P)

PURPOSE: This projectile is designed for target practice, warming rounds and other events to maximize safety.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body filled with inert homogeneous, dry material and fitted with a dummy nose plug. The base of the projectile is solid with a 1/2 caliber boattail and a copper rotating band to provide spin and obturation.

CONFIGURATION

OPERATIONAL DESCRIPTION: The projectiles are designed to be similar to the MK 64 family of projectiles in exterior shape and balance so they fly to the same spot. The projectile is completely inert to maximize safety during non-combat operations.

FUZEASSEMBLY LOAD BODY

DummyMK 92-1 Inert MK 64

NATIONAL STOCKNUMBER

1320-00-480-3389

PERFORMANCECHARACTERISTICS

PHYSICAL DATA

Length: 26 in. (66 cm)Weight: 70.00 lbs (31.75kg)Material: AISI 1050 Steel

5”/54 with MK 67 5”/62 with MK 67Range 25,294 yds*

(23,129 m)25,875 yds**(23,660 m)

Service Pressure

53.1 Ksi(366.1 MPa)

53.1 Ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft/sec(823 m/sec)


*Range Table - SW323-AB-ORD-020, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge. EDC = 0.5**Range Table - unpublished.


SW030-AA-MMO-010

C-10


PM4



MK 100 ALL UP ROUNDNon-Non-Fragmenting - Variable Time (NONFRAG VT)-VT)

PURPOSE: This projectile is designed for use in antiaircraft target practice, particularly against expensive drones. Firing results are usually observed without loss of the drone.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body filled with an inert material around a color burst unit. The color available is gray, designated by the color of C’s on the nose. A fuze cavity liner separates the fuze from the color burst unit and the inert filler. The base of the projectile is solid with a 1/2 caliber boattail and a copper rotating band to provide spin and obturation. The projectile is fitted with a Variable Time-Radio Frequency (VT-RF), proximity fuze. The MK 100-1 is shown.

CONFIGURATION

OPERATIONAL DESCRIPTION: The round is autonomous in its operation, as its action depends on the reflection of its transmitted signal from a target. When the RF signal strength is correct, the fuze fragments the nose of the projectile, ignites the color burst unit, allowing the release of the gray smoke cloud. Its reliability depends greatly on how close the gun system can place the round near the target. Should the round not pass close to a target, it will self-destruct on impact with the ground. The NONFRAG-VT round may be susceptible to some countermeasures and extraneous electromagnetic interference (EMI) and its detection radius is slightly reduced in the presence of sea clutter or EMI. Safety is provided by the fuze, which uses the gun’s setback and spin forces at launch to arm the round over 780 feet from the ship.

NoseMK 73-13

BoosterMK 39-0

MK 100-1 MK 64Color Burst Unit and Inert Fill

FUZEASSEMBLY BODYLOAD NATIONAL STOCKNUMBER

1320-01-013-3173

MK 100-2 MK 418-0(short

intrusion)MK 64

Color BurstUnit andInert Fill

1320-01-256-0709


PHYSICAL DATA

Length: 26 in. (66 cm)Weight: 69.40 lbs (31.48kg)Material: AISI 1050 Steel.

5”/54 with MK 67Range 25,294 yds*

(23,129 m)

Service Pressure

53.1 Ksi(366.1 MPa)

53.1 Ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft/sec(823 m/sec)


*Range Table - SW323-AB-ORD-020, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge.**Range Table - unpublished.

5”/62 with MK 67

25,875 yds**(23,660 m)

SW030-AA-MMO-010

C-11


PM4


PURPOSE: This high explosive round is designed for use against lightly armored surface targets or shore installations. Either instantaneous or delayed operation may be selected.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body filled with explosive Composition A-3. A fuze adapter separates the fuze from the explosive fill. The base of the projectile is solid with a ½-caliber boattail and a copper rotating band to provide spin and obturation. The projectile is fitted with a NATO shaped, Point Detonating/Delay (PD/D) fuze. The MK 108-1 projectile is shown.

CONFIGURATION

OPERATIONAL DESCRIPTION: The HE-PDD round provides an impact burst for use against a wide variety of surface targets, including lightly armored targets, urban targets, and earthwork fortifications. The round is immune to countermeasures as it uses a PD/D fuze that detonates on impact unless set to delay, where it will penetrate a target and then detonate milliseconds later inside. The round can reliably penetrate a quarter inch of steel when set to delay, which is done with a slot screwdriver. Safety is provided by the fuze, which uses the gun’s setback and spin forces at launch to arm the round over 310 feet from the ship.


PHYSICAL DATA

Length: 26.2 in. (66.5 cm)Weight:MK 108-1 = 69.63 lbs (31.58 kg)MK 108-2 = 69.06 lbs (31.33 kg)Material: AISI 1050 Steel.

5”/54 with MK 67 5”/62 with MK 67

Range 25,294 yds*(23,129 m)

25,875 yds** (23,660 m)

Service Pressure

53.1 ksi(366.1 MPa)

53.1 ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft./sec(823 m/sec)

BODYLOADFUZEASSEMBLY

MK 64

PressedComp A-3

(RDX)MK 399-0MK 108-1

MK 64Pressed

Comp A-3 (RDX)

MK 407-1MK 108-2


1320-01-023-9665

1320-01-120-3995

*Range Table - SW323-AB-ORD-020, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge **Range Table - unpublished

MK 108 ALL UP ROUNDHigh Explosive - Point Detonating Delay (HE-PDD)



SW030-AA-MMO-010

C-12


PM4


MK 127 ALL UP ROUNDHigh Explosive - Controlled Variable Time (HE-CVT)

PURPOSE: The HE-CVT round provides an air burst over land or water targets by using an active radio frequency fuze similar to the VT-RF round. However, the CVT feature keeps the round RF quiet until just beyond friendly troops providing extra overhead protection and less vulnerability to countermeasures. This RF round will not provide a burst against air targets as its sensitivity is optimized for a 30-foot burst over large land and water surfaces.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body with a metal rotating band and is loaded with explosive Composition A-3. A cavity liner separates the fuze from the main charge. The base of the MK 64 projectile body is solid with a ½-caliber boattail and a copper rotating band to provide spin and obturation. The projectile is fitted with a Controlled Variable Time (CVT) fuze.

CONFIGURATION

OPERATIONAL DESCRIPTION: The M728 fuze comes from the depot with a preset time delay setting. If a tactical situation requires the time to be changed, the M728 fuze can be manually set to the desired time with a fuze setting wrench before loading the projectile into the gun mount lower hoist. It operates only in the impact mode until a couple of seconds prior to the time set, which is when the electronics, including the RF broadcast, are activated. When the land or water surface is detected, the fuze functions the main charge and the lethal fragments are distributed. If the electronics malfunction, the fuze will self-destruct upon impact with the ground. Safety is provided by the fuze, which uses the gun’s setback and spin forces at launch to arm the round over 7,000 feet from the ship.


PHYSICAL DATA

Length: 26 in. (66 cm)Weight: 68.60 lbs (31.12 kg)Material: AISI 1050 Steel


(23,129 m)25,875 yds**(23,660 m)

Service Pressure

53.1 ksi(366.1 MPa)

53.1 ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft/sec(823 m/sec)

*Range Table - SW323-AB-ORD-020, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge**Range Table - unpublished


MK 64Pressed

Comp A-3(RDX)

M728MK 127-0 1320-01-064-2664




SW030-AA-MMO-010

C-13


PM4


MK 156 ALL UP ROUNDHigh Explosive - Infrared (HE-IR)

PURPOSE: The HE-IR round provides an air burst for defense against fast moving air targets. The round is virtually immune to countermeasures as it uses a passive IR fuze that operates only on the infrared spectrum detected in the exhaust gasses of jet and hot missile targets. Being on an unguided bullet, it cannot be decoyed away. It is not intended for use against non-powered missiles, propeller aircraft, or to detect the exhaust from ships’ stacks.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body loaded with explosive Composition A-3. A fuze adapter separates the fuze from the main charge. The base of the projectile is solid with a 1/2 caliber boattail and a copper rotating band to provide spin and obturation. The projectile is fitted with a NATO shaped, Variable Time-Infrared (VT-IR) fuze.

CONFIGURATION

OPERATIONAL DESCRIPTION: The fuze is autonomous in its operation as it waits for IR energy in the proper wavelength, intensity, and direction before it detonates the HE round in close proximity to the target. Its effectiveness depends greatly on how close the gun system can place the round to the target. Should the round not pass close to a target, it will self-destruct on impact with the ground. Safety is provided by the fuze, which uses the gun’s setback and spin forces at launch to arm the round over 780 feet from the ship.


PHYSICAL DATA



(23,129 m)25,875 yds**(23,660 m)

Service Pressure

53.1 ksi(366.1 MPa)

53.1 ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft/sec(823 m/sec)

MK 404MK 156-5 MK 64Pressed

Comp A-3 (RDX)


1320-01-350-4216

*Range Table - SW323-AB-ORD-020, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge**Range Table - unpublished



SW030-AA-MMO-010

C-14


PM4



PURPOSE: The HE-CVT round provides an air burst over land or water targets by using an active radio frequency fuze similar to the VT-RF round. However, the CVT feature keeps the round RF quiet until just beyond friendly troops providing extra overhead protection and less vulnerability to countermeasures. This RF round will not provide a burst against air targets as its sensitivity is optimized for a 30 foot burst over large land and water surfaces.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body with a metal rotating band and is loaded with explosive Composition A-3. A cavity liner separates the fuze from the main charge. The base of the MK 64 projectile body is solid with a 1/2 caliber boattail and a copper rotating band to provide spin and obturation. The projectile is fitted with a NATO shaped, Controlled Variable Time-Radio Frequency (CVT-RF) fuze.

CONFIGURATION

OPERATIONAL DESCRIPTION: This HE-CVT round is automatically set by the gun mount or by hand to a time setting corresponding to the time of flight to the target less several seconds. It operates only in the impact mode until a couple of seconds prior to the time set, which is when the electronics, including the RF broadcast, are activated. When the land or water surface is detected, the fuze functions the main charge and the lethal fragments are distributed. If the electronics malfunction, the fuze will self-destruct upon impact with the ground. Safety is provided by the fuze, which uses the gun’s setback and spin forces at launch to arm the round over 260 feet from the ship.


PHYSICAL DATA

Length: 26 in. (66 cm)Weight: 68.69 lbs (31.16 kg)Material: AISI 1050 Steel.


(23,129 m)25,875 yds**(23,660 m)

Service Pressure

53.1 ksi(366.1 MPa)

53.1 ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft/sec(823 m/sec)

M732MK 157-0 MK 41Pressed

Comp A-3(RDX)

ASSEMBLY BODYLOAD NATIONAL STOCKNUMBER

1320-01-350-8052

MK 157-2 M732 MK 64Pressed

Comp A-3(RDX)

1320-01-350-4219


*Range Table - SW323-AB-ORD-020, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge. **Range Table - unpublished.

FUZE


SW030-AA-MMO-010

C-15


PM4



PURPOSE: The HE-CVT round provides an air burst over land or water targets by using an active radio frequency fuze similar to the VT-RF round. However, the CVT feature keeps the round RF quiet until just beyond friendly troops providing extra overhead protection and less vulnerability to countermeasures. This RF round will not provide a burst against air targets as its sensitivity is optimized for a 30 foot burst over large land and water surfaces.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body loaded with PBXN-106 Insensitive Munitions (IM) explosive. The nose is fitted with a boostered fuze adapter also containing PBXN-106 IM and sealed by an aluminum lid, thereby permitting contact fuze replacement (ashore only). The base of the projectile body is solid with a 1/2 caliber boattail and a copper rotating band to provide spin and obturation. The projectile is fitted with a NATO shaped, Controlled Variable Time-Radio Frequency (CVT-RF) fuze.

CONFIGURATION

OPERATIONAL DESCRIPTION: The HE-CVT round is automatically set by the gun mount or by hand to a time setting corresponding to the time of flight to the target less several seconds. It operates only in the impact mode until a couple of seconds prior to the time set, which is when the electronics, including the RF broadcast, are activated. When the land or water surface is detected, the fuze functions the main charge and the lethal fragments are distributed. If the electronics malfunction, the fuze will self-destruct upon impact with the ground. Safety is provided by the fuze, which uses the gun’s setback and spin forces at launch to arm the round over 260 feet from the ship.


PHYSICAL DATA



(23,129 m)25,875 yds**(23,660 m)

Service Pressure

53.1 ksi(366.1 MPa)

53.1 ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft/sec(823 m/sec)


MK 64Cast

PBXN-106 IM

M732MK 158-0 1320-01-350-0236





SW030-AA-MMO-010

C-16


PM4


MK 160 ALL UP ROUNDHigh Explosive - Point Detonating Delay (HE-PDD)

PURPOSE: This high explosive round is designed for use against lightly armored surface targets or shore installations. Either instantaneous or delayed operation may be selected.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body loaded with PBXN-106 Insensitive Munitions (IM) explosive. The nose is fitted with a boostered fuze adapter containing PBXN-106 IM. A sealed aluminum lid separates the fuze from the main charge. The base of the projectile is solid with a 1/2 caliber boattail and a copper rotating band to provide spin and obturation. The projectile is fitted with a NATO shaped, Point Detonating/Delay (PD/D) fuze.

CONFIGURATION

OPERATIONAL DESCRIPTION: The HE-PDD round provides an impact burst for use against a wide variety of surface targets, including lightly armored targets, urban targets, and earthwork fortifications. The round is immune to countermeasures as it uses a PDD fuze that detonates on impact unless set to delay, where it will penetrate a target and then detonate milliseconds later inside. The round can reliably penetrate a quarter inch of steel when set to delay, which is done with a slot screwdriver. Safety is provided by the fuze, which uses the gun’s setback and spin forces at launch to arm the round over 310 feet from the ship.


PHYSICAL DATA



(23,129 m)25,875 yds** (23,660 m)

Service Pressure

53.1 ksi(366.1 MPa)

53.1 ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft/sec(823 m/sec)


MK 64Cast

PBXN-106 IM

MK 407MK 160-0 1320-01-370-3695

NATIONAL STOCK NUMBER




SW030-AA-MMO-010

C-17


PM4


MK 173 ALL UP ROUNDHigh Explosive - Mechanical Time/Point Detonating

(HE-MT/PD)

PURPOSE: The HE-MT/PD round provides either a timed air burst or an impact burst for use against a wide variety of targets. The round is immune to countermeasures as it uses a Mechanical Time/Point Detonating (MT/PD) fuze.

PHYSICAL DESCRIPTION: This projectile consists of a forged steel body loaded with explosive Composition A-3. A fuze adapter separates the fuze from the main charge. The base of the projectile is solid with a ½-caliber boattail and a copper rotating band to provide spin and obturation. The projectile is fitted with a NATO shaped, MT/PD fuze.

CONFIGURATION

OPERATIONAL DESCRIPTION: The mechanical time feature uses a clock assembly that functions the round at the set time, which ranges from 3 to 95 seconds. The PD feature is selectable and is a back-up, self-destruct feature should the timer not function prior to impact with the ground. The round is set automatically by the gun mount’s fuze setter, or it can be set by a hand wrench. Safety is provided by the fuze, which uses the gun’s setback and spin forces at launch to arm the round over 360 feet from the ship.


PHYSICAL DATA



(23,129 m)25,875 yds**(23,660 m)

Service Pressure

53.1 ksi(366.1 MPa)

53.1 ksi(366.1 MPa)

Muzzle Velocity

2,650 ft/sec(808 m/sec)

2,700 ft/sec(823 m/sec)

MK 393-0MK 173-0 MK 64Pressed

Comp A-3 (RDX)


1320-01-426-3175

*Range Table - SW323-AB-ORD-020, 5-Inch 54 Caliber Surface with MK 67 Propelling Charge. ** Range Table - unpublished.



SW030-AA-MMO-010

C-18

Figure C-16 MK 393 MOD 0 Mechanical Time/Point Detonating Fuze

SW030-AA-MMO-010

C-19

Figure C-17 MK 399 MOD 1 Point Detonating/Delay Fuze

SW030-AA-MMO-010

C-20

Figure C-18 MK 404 MOD 2 Variable Time Infrared (VT-IR)

PM4

The MK 404 fuze provides the fleet a proven round for defense against fast moving air targets. The fuze is virtually immune to countermeasures as it uses passive IR technology which operates only on the infrared spectrum detected in the exhaust gasses of jet and hot missile targets. It is not intended for use against non-powered missiles, propeller aircraft, or against surface ships. The fuze is autonomous in its operation as it waits for IR energy in the proper wavelength, intensity, and direction before it detonates the HE round in close proximity to the target. Its effectiveness depends greatly on how close the gun system can place the round near the target. Should the round not pass close to a target it will self-destruct on impact with the ground.

MK 404 MOD 2 Variable Time Infrared (VT-IR)MK 404 MOD 2 Variable Time Infrared (VT-IR)

Introduction

On gun firing, the setback and spin environments activate the reserve energizer and the (S&A), which provides over 780 feet of safe separation distance prior to arming. As the round nears a target, optical energy is passed through a sapphire window filter, through a lens and onto a detector. The detector converts the energy into electrical impulses, which are amplified and fed to the signal processing circuit. When the signal reaches a certain amplitude the firing circuit initiates the detonation train.

Operation

Proximity Fuze

Window

FilterOptics

Assembly

MonitorElectronics

ReserveEnergizer

MK 42 MOD 3Rear Fitting

Safety Device

BoosterSteel

Diaphragm

Sleeve

FrontCase

SW030-AA-MMO-010

C-21

Figure C-18 MK 404 MOD 2 Variable Time Infrared (VT-IR) (Continued)

Characteristics

For More Information Contact

MK 404 MOD 2 Variable Time Infrared (VT-IR) MK 404 MOD 2 Variable Time Infrared (VT-IR)

Overall Size Intrusion Ballistic Levels Energetic ComponentsWT: 2.1 lb. (953 g)

LG: 5.7 in. (145.2 mm)

XSECT: 2.4 in. (61 mm)

DP: 2.21 in. (55.9 mm)

Sleeve DIA: 1.75 in. (44.5 mm)

THD: 2.000-12 UN – 2A

THD DP: 0.902 in. (22.9 mm)

Rotation: 410 rps

Setback: 26,000 g

Velocity: 3,000 ft/s (914 m/s)Detonator, Electric, MK 71-0PETN (.04 g), Lead Azide (0.08 g)

Detonator, Relay, MK 64-0Lead Azide (0.135 g)

Lead, DWG 5467883PBXN-5 (100 mg)

Booster, DWG 2512814CH-6 (11 g)

Weapons Ammunition Arming Safety

UNO Serial Number Safety Standard Hero Assessment Environmental &Performance Standard

5-in MK 45

76-mm/62 MK 75

5-in HE-IR, HI-FRAG,and Puff projectiles

76-mm/62-caliber HE-IR projectiles

FIRST SAFETY900 g No Arm1,385 g All Arm

SECOND SAFETY40 rps No Arm145 rps All Arm

0409 STANAG 4187MIL-STD-1316C HERO Safe MIL-STD-331B

Proximity Fuze

NSWC Dahlgren Division17320 Dahlgren Road

Dahlgren, VA 22448-5100

Fuze Branch – Code, G34

NSWC Dahlgren Division

Voice: 540-653-5493

DSN: 249-5493

FAX: 540-653-5503


SW030-AA-MMO-010

C-22

Figure C-19 MK 407 MOD 1 Point Detonating/Delay Fuze

PM4

The MK 407 MOD 1 provides the fleet a point detonating (PD) or delay action fuze to burst upon impact or punch through hardened targets. The PD mode is the default setting. The delay mode provides improved effectiveness against enclosed targets by penetrating the target before detonating. This is on the only round (HE-PDD) in the fleet with this penetration capability.

MK 407 MOD 1 Point Detonating/Delay FuzeMK 407 MOD 1 Point Detonating/Delay Fuze

Introduction

The fuze is manually set with a slot screwdriver for point detonating or delay function. On firing, the setback pin beneath the (S&A) rotor is retracted into the lead block and locked down by spin. The rotor detents in the S&A are withdrawn by spin, allowing the rotor to turn to the armed position. Arming is delayed for 310 feet by the gear train escapement. On impact, the firing pin initiates the stab detonator. Flash from the stab detonator passes down two branches in the flash channel initiating the nominal 8-ms delay assembly in one branch. The PD or Delay mode is determined by the orientation of an interrupter in the other branch. When set PD, a relay detonator in the interrupter is aligned in the channel. The relay functions instantaneously from the flash of the stab detonator and before the delay in the other branch can produce an output. When set Delay, the interrupter blocks the PD flash channel and the relay detonator does not fire. The branches converge in front of the armed S&A. Output from either the PD relay or delay assembly will initiate the rotor detonator, which was aligned with the end of the flash tube during arming and, in turn, fires the two MK 8 leads and booster pellet.

Operation

RAIN SHIELD

FIRING PIN

DETONATOR(SEE DETAIL

AT RIGHT)

HEAD

HARDENEDBODY

PLASTIC INSERT

RELAYDETONATOR

PYROTECHNIC DELAY

ASSEMBLY

LEADS

BOOSTER

POINT DETONATING ELEMENT ASSEMBLY

SPACER

STAB DETONATOR

SELECTOR SW ITCH ASSEMBLY

REAR FITTING SAFETY DEVICE

ANTI- MALASSEMBLY PIN

SW030-AA-MMO-010

C-23

Figure C-19 MK 407 MOD 1 Point Detonating/Delay Fuze (Continued)

Characteristics


Overall Size Intrusion Ballistic Levels Energetic ComponentsWeight: 2.1 lb. (953 g)

Length: 5.955 in.(151 mm)

Cross Section: 2.4 in.(61 mm)

Intrusion Depth: 2.21 in. (56 mm)

Sleeve Diameter: 1.755 in.(44.5 mm)

Thread: 2.0 -12 UNS - 2A

Thread Depth: 0.90 in. (22.9 mm)

Rotation: 410 rps

Setback: 26,000 g

Velocity: 3,000 ft/s (914 m/s)

Detonator, Stab Assembly, DWG 558121 NOL 130 (78 mg),Lead Azide (200 mg)

Delay Assembly, DWG 5177539Input NOL 130 (21 mg), Delay Lead Styphnate (16 mg),Output Lead Azide (10 mg),Igniter FA878 (164 mg)

Detonator, Relay, MK 29-0Lead Azide (160 mg)

Detonator (used in rotor),MK 50 Lead Azide (216 mg),

Tetryl (90 mg)

Lead, Explosive,MK 8 MOD 0 (2 used) CH-6, (188 mg each, 376 mg total)

Booster Pellet, DWG 2512814CH-6 (11.2 g)



5-in MK 45

76-mm/62 MK 75

5-in HE & HI-FRAGprojectiles

76-mm/62-caliber HE projectiles

FIRST SAFETY (Set Back)900 g No Arm1385 g All Arm

SECOND SAFETY (Spin)50 rps No Arm75 rps All Arm

0409 STANAG 4187MIL-STD-1316C

HERO Safe MIL-STD-331A

MK 407 MOD 1Point Detonating/Delay FuzeMK 407 MOD 1Point Detonating/Delay Fuze





Voice: 540-653-5493

DSN: 249-5493

FAX: 540-653-5503


SW030-AA-MMO-010

C-24

Figure C-20 MK 418 MOD 0 Variable Time - Radio Frequency Proximity Fuze

SW030-AA-MMO-010

C-25

Figure C-20 MK 418 MOD 0 Variable Time - Radio Frequency Proximity Fuze

SW030-AA-MMO-010

C-26

Figure C-21 MK 419 MOD 0 Multi-Function Fuze (MFF)

PM4

MFF provides the fleet with a state-of-the-art, RF-based, all-purpose fuze that maximizes mission flexibility and magazine effectiveness. The fuze can be set to provide optimum performance against air, surface and land targets using the MK 34 Inductive Setter in the 5-Inch MK 45 Gun Mount.

The fuze can be set in one of five modes: air target (AIR), height-of-burst (HOB), electronic time (ET), point detonation (PD), and a settable or default autonomous (AUT) mode. All modes include a selectable self-destruct PD backup.

In the AIR mode, MFF is provided the estimated time of flight and closing velocity of the air target to optimize its burst position. The HOB mode provides similar capabilities as (CVT) fuzes, where the RF broadcast is delayed to maximize overhead safety. HOB settings from 65 feet above the surface to negative bursts below a dense canopy are settable in 5-ft increments. The ET mode is settable in 10 ms increments out to burst times of 135 seconds. The PD mode is set to detonate upon impact with a target. The default mode is the AUT mode, in which MFF looks for an air target for the first segment of flight and then switches to a 25-ft HOB for the remainder of the flight.

MK 419 MOD 0 Multi-Function Fuze (MFF)MK 419 MOD 0 Multi-Function Fuze (MFF)

Introduction

Just prior to gun firing, the fuze mode and target-specific engagement parameters are inductively set by the MK 34 Electronic Fuze Setter through the maglink assembly. On gun firing, the setback and spin environments activate the reserve energizer and the (S&A). Additional safety is provided via the microcontroller, which delays charging the firing capacitor until the projectile is in the vicinity of the target, thus providing over-head safety. When the target is detected, a fire signal causes the firing capacitor to discharge through the detonator which, in turn, initiates the lead, booster, and main projectile charge.

Operation

PD Impact Switch

RadomeAssemblyRF Antenna

Cone Assembly

Steel Crimp Ring

MAGLINKAssembly

Processing& ControlElectronicsAssembly

ReserveEnergizer

DetonatorCollar Assembly

BoosterAssembly

VoltageRegulator &Firing Circuit

Sleeve

EX 60 S&ADevice

SW030-AA-MMO-010

C-27/(C-28 blank)

Figure C-21 MK 419 MOD 0 Multi-Function Fuze (MFF)




Overall Size Intrusion Ballistic Levels Energetic Components

WT: 2.05 lb. (931 g)

LG: 5.97 in. (152 mm)

XSECT: 2.4 in. (61mm)

DP: 2.21 in. (56 mm)

Sleeve DIA: 1.827 in. (46.4 mm)

THD: 2.0 - 12 UNS – 1A

THD DP: 0.76 in. (19 mm)

Rotation: 410 rps

Setback: 26,000 g

Velocity: 3,075 ft/s (937 m/s)

Detonator, Electric, DWG 5620036DXN1 (68 mg)

Lead, DWG 7100480PBXN-5 (226 mg)

Booster, DWG 7100397PBXN-5 (9 g)



5-in MK 45

76mm/62 MK 75*

*Validation Required

5” HE projectiles

76-mm/62-caliber HE projectiles

FIRST SAFETY (Set Back)2,000 g No Arm3,000 g All Arm

SECOND SAFETY (Spin)70 rps No Arm120 rps All Arm

0409 STANAG 4187MIL-STD-1316D

HERO Safe MIL-STD-331B

Arming Distance5-in/54 MK 45 MOD 1,2)890 – 1,400 ft. (271 - 423 m)

76mm/62 MK 75630 – 1,020 ft. (192 - 308 m)



Voice: 540-653-5493

DSN: 249-5493

FAX: 540-653-5503


SW030-AA-MMO-010

D-1

MM1 - Propellant ............................................................................................................................................... Table A-1M10 - Links, Disintegrating .............................................................................................3-2.3.2., Figure 3-4, 3-2.3.3.M103 - Case, Cartridge, Brass ........................................................................................................Table 3-1, 3-2.3.1.2.M103A1 - Case, Cartridge, Steel ..................................................................................................................... 3-2.3.1.2.M204 - Cartridge, 20-Millimeter .................................................... 3-2.1., 3-2.3.3., 3-2.3.3.1.1., Table 3-3, 3-2.3.3.2.M210 - Cartridge, 20-Millimeter .......................................................... 3-2.1., 3-2.3.3., 3-2.3.3.1.2., Table 3-3, 3-2.4.M21A1 - Case, Cartridge, Brass ...................................................................................Table 3-2, 3-2.3.2.3., Table 3-3M27 - Fuze Setter .......................................................................................................................Figure B-4, Table B-1M28 - Links, Disintegrating ............................................................................................................................... 3-3.3.3.M36 - Fuze Setter .......................................................................................................... B-1.3., Figure B-5, Table B-2M36A1 - Primer, Percussion ..........................................................................................................Table 3-2, 3-2.3.2.3.M5 - Canister .................................................................................................................................................. Table A-2M505A3 - Fuze, Point Detonating ......................... 3-2.3.3.1.2., Table 3-3, 3-3.3.1.3., Table 3-4, 4-2.5., Figure 4-10M513A2 - Fuze, Variable Time, Controlled ............................................................................................... Figure 4-40M514A1 - Fuze, Variable Time, Controlled ............................................................................................... Figure 4-40M52A3B1 - Primer, Electric ...........................................................................Table 3-1, 3-2.3.1.2., 5-3.4., Figure 5-4M55A2 - Cartridge, 20-Millimeter ..................................................................................3-2.1., 3-2.3.1.1.1., Table 3-1M6 - Propellant .............................................................................................................................................. Table 3-11M66 - Fuze, Base Detonating ..........................................................................................................................A-6.6.2.5.M7 - Links, Loading ...................................................................................................3-2.2.1., 3-2.3.1.1.2., Figure 3-2M728 - Fuze, Variable Time, Controlled ......................................... 4-5.5.2., Figure 4-30, Figure 4-38, Figure 4-41M732 - Fuze, Controlled variable time - Radio Frequency ........................................Table 3-11, 4-5.5.1.1., Table 4-7M75 - Fuze, Point Detonating .....................................................................................................A-4.1.1., Figure A-52M791 - Cartridge, 25-Millimeter ....................................................................3-3.1., 3-3.3.1.1., Figure 3-9, Table 3-4M793 - Cartridge, 25-Millimeter ........................................................................................3-3.1., 3-3.3.1.2., Table 3-4M794 - Cartridge, 25-Millimeter ........................................................................................3-3.1., Table 3-4, 3-3.3.1.5.M8 - Links, Disintegrating ...............................................................................................3-2.3.2., Figure 3-4, 3-2.3.3.M81A1 - Body, Projectile ............................................................................................................................... Table A-1M95 - Cartridge, 20-Millimeter ......................................................................3-2., 3-2.3.2.2.1., Table 3-2, Figure 3-5M96 - Cartridge, 20-Millimeter ......................................................................3-2., Table 3-2, 3-2.3.2.2.2., Figure 3-6M99 - Cartridge, 20-Millimeter ............................................................... 3-2., 3-2.3.2., Table 3-2, 3-2.3.2.2.3., 3-2.4.MK 1 - Dummy Propelling Charge ................................................................................................................ Table A-2MK 10 - Case, Cartridge, Steel ....................................................................................................................... Table A-3MK 100 - Fuze, Variable Time ...................................................................................................................... Table 3-12MK 107 - Fuze, Infrared ................................................................................................................................ Table 3-12MK 108 - Fuze, Point Detonating .................................................................................................................. Table 3-12MK 109 - Fuze, Dummy Nose Plug .............................................................................................................. Table 3-12MK 11 - Case, Cartridge, Steel ....................................................................................................................... Table A-3MK 11 - Filler, Illuminating ........................................................................................................................... Table A-2MK 11 - Plug, Closure, Polyurethane ............................................................................................................. Table A-3MK 11 - Tracer ................................................................................................................ Table A-1, A-3.1.5.5., A-6.4.MK 116 - Fuze, Variable Time ...................................................................................................................... Table 3-12MK 117 - Fuze, Variable Time, Self Destruct ............................................................................................... Table 3-12MK 118 - Fuze, Mechanical Time ................................................................................................................. Table 3-12MK 12 - Filler, Illuminating .......................................................................................................Table A-11, A-6.6.2.6.MK 127 - Fuze, Controlled Variable Time ................................................................................................... Table 3-12

APPENDIX D

MARK INDEX

MARK / NOMENCLATURE PARAGRAPH / TABLE / FIGURE

SW030-AA-MMO-010

D-2

APPENDIX D (Continued)


MK 128 - Fuze, Mechanical Time/Point Detonating .....................................................................................Table 3-12MK 13 - Primer, Combination ........................................................................................................ Table A-3, A-3.5.5.MK 14 - Canister .............................................................................................................................................. 3-8.4.1.5.MK 14 - Tracer .................................................................................................................................. Table A-1, A-6.5.MK 15 - Primer, Combination .......................................................................................... 5-5.1., 5-5.1.1., Figure 5-10MK 156 - Fuze, Infrared ................................................................................................................................Table 3-12MK 157 - Fuze, Controlled Variable Time ....................................................................................................Table 3-12MK 158 - Fuze, Controlled Variable Time ....................................................................................................Table 3-12MK 160 - Fuze, Point Detonating/Delay .......................................................................................................Table 3-12MK 165 - Infrared ..........................................................................................................................................Table 3-12MK 170 - Fuze, Infrared ................................................................................................................................Table 3-12MK 173 - Fuze, Mechanical Time/Point Detonating .....................................................................................Table 3-12MK 174 - Fuze, Multi-Function .....................................................................................................................Table 3-12MK 179 - Fuze, Electronic Time ...................................................................................................................Table 3-12MK 182 - Fuze, Electronic Time ...................................................................................................................Table 3-12MK 19 - Fuze, Base Detonating ...................................................................................................................... Table A-6MK 2 - Body, Projectile .................................................................................................................................. Table A-1MK 2 - Case, Cartridge, Brass ........................................................ 3-5.4., Table 3-7, Table A-1, A-3.1.6., Table A-7MK 20 - Primer, Percussion ............................................................................................................................... A-5.5.2.MK 21 - Fuze, Base Detonating ...................................................................................................................... Table A-4MK 22 - Body, Projectile ................................................................................................................................ Table A-6MK 22 - Primer, Percussion ............................. 3-5.4., Table 3-7, Table 5-1, 5-4.3., Figure 5-8, Table A-1, A-3.1.6.MK 23 - Detonator ........................................................................................................................................... 4-2.3.3.5.MK 24 - Body, Projectile ................................................................................................................................ Table A-6MK 244 Mod 0 .................................................................................................................................................Table 3-1MK 25 - Body, Projectile .............................................................................................................................. Table A-11MK 25 - Detonator ......................................................................................................................... 4-2.3.2.3., 4-2.3.3.2.MK 25 - Fuze Mechanical Time ...................................................................................................Table A-4, Table B-1MK 25 - Projectile, 3-Inch, 50-Caliber ......................................................................................................... Table A-11MK 25 - Projectile, 8-Inch 55-Caliber ............................................................................................................ Table A-6MK 27 - Body, Projectile ...........................................................................................................A-6.6.2.2.3., A-6.6.2.3.MK 27 - Fuze, Point Detonating ............................................................. A-3.1.5.5., A-3.1.5.6., A-3.1.5.7., A-3.1.5.8.MK 27 - Projectile, 3-Inch, 50-Caliber .......................................................................................................Figure A-63MK 27- Fuze, Point Detonating ...................................................................................................................... A-3.1.5.9.MK 28 - Fuze, Base Detonating ................................................................................................... Table A-2, Table A-4MK 29 - Body, Projectile .............................................................................................................................. Table A-11MK 29 - Detonator ......................................................................................................................... 4-2.3.3.3., 4-2.3.3.4.MK 29 - Fuze, Point Detonating ....................................................................................................................Figure 4-6MK 295 MOD 0 - Cartridge, High Explosive, Pre-fragmented, Programmable, Proximity (HE-3P)

fuzed round ........................................................................................................................................Table 3-8MK 296 MOD 0 - Cartridge, Target Practice (TP) round ...............................................................................Table 3-8MK 30 - Body, Projectile ................................................................................................................................ Table A-2MK 30 - Fuze, Booster ..................................................................................................................... 4-5.1.2., Table A-2MK 30 - Fuze, Point Detonating ......................................................................................... 4-2.2., 4-2.2.1., Figure 4-3MK 31 - Body, Projectile .............................................................................................................................. Table A-11MK 31 - Primer ................................................................................................................................................Table 3-2MK 31 - Projectile, 3-Inch, 50-Caliber ......................................................................................................... Table A-11MK 32 - Body, Projectile ................................................................................................................................ Table A-2

SW030-AA-MMO-010

D-3



MK 33 - Body, Projectile .............................................................................................................................. Table A-11MK 33 - Projectile, 3-Inch, 50-Caliber .................................................................................. Table A-11, Figure A-62MK 34 - Body, Projectile ........................................................................................... Table A-2, Table A-4, A-3.5.4.1.MK 342 - Mechanical Time Fuze .................................................................................................... 4-3.7., Figure 4-13MK 35 - Body, Projectile ........................................................................................... Table A-2, Table A-4, A-3.5.4.6.MK 35 - Primer, Combination ................................................................ Table A-7, Table A-10, A-5.5., Figure A-57MK 35 - Projectile, 5-Inch, 38-Caliber ........................................................................................................... Table A-2MK 36 - Body, Projectile ............................................................................................................Table A-4, Table A-11MK 37 - Body, Projectile ................................................................................................................................ Table A-4MK 37 - Primer, Electric ..................................................... Table A-7, A-3.6.5.1., A-5.1., Table A-10, Figure A-53MK 379 - Fuze, Auxiliary Detonating ............................................................................................................ Table A-2MK 38 - Body, Projectile ................................................................................................................................ Table A-2MK 38 - Primer, Electric ..................................................... Table A-7, A-3.6.5.1., Table A-10, A-5.2., Figure A-54MK 384 - Fuze, Auxiliary Detonating ............................................................................................................ Table A-2MK 39 - Fuze, Booster ................................................................................................................................... Table A-2MK 39 - Primer, Electric ........................................................ A-3.5.5., Table A-5, Table A-10, A-5.3., Figure A-55MK 393 - Fuze, Mechanical Time .................................................................... Figure 4-14, 4-3.8., B-1.2., Table B-1MK 395 - Fuze, Auxiliary Detonating ......................................................................... 4-7.3., Table 4-14, Figure 4-63MK 396 - Fuze, Auxiliary Detonating ......................................................................... 4-7.3., Table 4-14, Figure 4-64MK 399 - Fuze, Point Detonating ...................................................................................................... 4-2.3., Figure 4-7MK 40 - Body, Projectile ................................................................................................................................ Table A-4MK 40 - Primer, Electric ........................................................ A-3.5.5., Table A-5, Table A-10, A-5.4., Figure A-56MK 403 - Fuze, Mechanical Time ....................................................................................Table A-2, B-1.2., Table B-1MK 404 - Firing Circuits ........................................................................................................... Figure 4-53, 4-5.6.8.3.MK 404 - Fuze Signal Processor ............................................................................................... 4-5.6.8.2., Figure 4-52MK 404 - Fuze, Variable Time-Infrared ...................................................................................Table 3-11, Table A-11MK 407 - Fuze, Point Detonating .............................................................. Table 3-11, 4-2.4., Figure 4-8, Figure 4-9MK 41 - Body, Projectile ................................................................................................................................ Table A-4MK 41 - Delay Arming Safety Device .................. 4-2.3.2.2., 4-2.3.2.3., 4-2.3.3.1., 4-2.3.3.3., 4-7.3.1., Figure 4-62MK 41 - Primer, Percussion .......................................................................................... Table A-10, A-6.6.3., A-6.6.4.MK 411 - Fuze, Auxiliary Detonating ......................................................................... 4-7.3., Table 4-14, Figure 4-65MK 413 - Fuze, Auxiliary Detonating ............................................................................................................ Table A-2MK 417 - Fuze, Signal Processor ........................................................................................... 4-5.1.8.6.2., Figure 4-23MK 417 - Fuze, Variable Time-Radio Frequency ......................................Table 3-11, Table 4-1, 4-5.3., Figure 4-25MK 418 - Fuze, Circuit Schematic .............................................................................................................. Figure 4-23MK 418 - Fuze, Variable Time-Radio Frequency ......................................................... Table 4-1, 4-5.4., Figure 4-26MK 42 - Body, Projectile ................................................................................................................................ Table A-4MK 42 - Primer, Electric ...........................................................................Table A-10, Table A-11, A-6.6.3., A-6.6.4.MK 423 - Fuze, Electronic ............................................................................................................................. Table A-8MK 43 - Fuze, Auxiliary Detonating .............................................................................................................. Table A-2MK 43- Body, Projectile ................................................................................................................................. Table A-4MK 44 - Body, Projectile ................................................................................................................................ Table A-2MK 44 - Fuze, Auxiliary Detonating ..........................................................................................Table A-2, Table A-11MK 44 - Primer, Electric .............................................................................................................................. Table A-10MK 442 - Fuze ............................................................................................................................................... Table 3-10MK 45 - Primer, Electric ................................................................................................. Table 5-1, 5-3.2., Figure 5-2MK 46 - Body, Projectile ................................................................................................................................ Table A-2MK 47 - Body, Projectile ................................................................................................................................ Table A-2MK 47 - Monitor ..................................................................................................................................4-5.3.2., 4-5.3.5.

SW030-AA-MMO-010

D-4



MK 48 - Fuze, Base Detonating ................................................................................................... Table A-6, Table A-8MK 48 - Primer, Electric .............................................................Table 5-1, 5-3.3., Figure 5-3, Table A-3, A-3.3.6.1.MK 49 - Body, Projectile ................................................................................................................................ Table A-2MK 49 - Delay Arming Safety Device ................................................................................................ 4-2.4.2., 4-2.4.3.MK 50 - Body, Projectile ................................................................................................................................ Table A-2MK 50 - Fuze, Mechanical Time ................................................................................................. Table A-2, Table A-4MK 51 - Body, Projectile ................................................................................................................................ Table A-2MK 51 - Fuze, Mechanical Time ................................................................ Table A-11, A-6.6.2.4., A-6.6.2.6., B-1.2.MK 52 - Body, Projectile ................................................................................................................................ Table A-2MK 52 - Fuze, Auxiliary Detonating .......................................................4-5.5.8.7., Table A-2, Table A-4, Table A-6MK 54 - Fuze, Auxiliary Detonating 4-7.2., Figure 4-61, Table A-2, Table A-4, Table A-6, Table A-11, A-6.6.2.4.MK 55 - Electric Firing Circuit ....................................................................................................................Figure 5-11MK 55 - Fuze, Auxiliary Detonating ........................................................................................Figure 4-61, Table A-8MK 56 - Body, Projectile ................................................................................................................................ Table A-2MK 57 - Body, Projectile ................................................................................................................................ Table A-2MK 6 - Fuze, Dummy Nose Plug ..................................................................................................................Table 3-12MK 61 - Fuze, Mechanical Time .................................................................................................................... Table A-2MK 62 - Rocket Motor, Solid Propellant ........................................................................................................ A-3.3.5.4.MK 63 - Propelling Charge, Full .................................................................................................................... Table A-3MK 64 - Fuze, Base Detonating .......................................................................................................................... 4-2.3.1.MK 64 - Propelling Charge, Reduced ........................................................................................................ 3-8.7., 3-8.8.MK 64 - Rocket Motor Solid Propellant ......................................................................................................... A-3.4.4.2.MK 65 - Clearing Charge ................................................................................................................................ Table A-3MK 66 - Body, Projectile ................................................................................................................................ Table A-2MK 66 - Fuze, Point Detonating ....................................................................................................................Figure 4-5MK 67 - Propelling Charge, Full ............................................................................................................... 3-8.7., 3-8.8.MK 68 - Projectile, 20-Millimeter ............................................................................................3-2.3.1.1.2., Figure 3-1MK 68 - Propelling Charge, Reduced ........................................................................................................ 3-8.7., 3-8.8.MK 7 - Case, Cartridge, Brass .......................................................................................Table A-11, A-6.6.3., A-6.6.4.MK 71 - Fuze, Variable Time-Radio Frequency ............................................................................. 4-5.1.1., Table A-2MK 73 VT-RF Fuze ........................................................................................ 4-5.1.1., Table 4-2, 4-5.2., Figure 4-24MK 8 - Case, Cartridge, Brass ........................................................................................................................ Table A-3MK 80 - Fuze, Point Detonating ....................................................................................................................Table 3-12MK 81 - Fuze, Controlled Variable Time ......................................................................................................Table 3-12MK 82 - Mechanical Time/Point Detonating ................................................................................................Table 3-12MK 88 - Fuze, Mechanical Time ...................................................................................................................Table 3-12MK 9 - Case, Cartridge, Steel ........................................................................ Table A-11, A-6.6.3., A-6.6.4., A-6.6.5.MK 90 - Fuze, Point Detonating ....................................................................................................................Table 3-12MK 90-Series Fuze Signal Processor ............................................................................................................... 4-5.6.8.1.MK 91 - Fuze, Mechanical Time ...................................................................................................................Table 3-12MK 91 - VT-IR Fuze .......................................................................................................................4-5.7., Figure 4-54MK 92 - Fuze, Dummy Nose Plug ................................................................................................................Table 3-12MK 96 - Fuze, Mechanical Time ...................................................................................................................Table 3-12MK 97 - Fuze, Point Detonating ....................................................................................................................Table 3-12

SW030-AA-MMO-010

E-1

A661 - Cartridge, 20-Millimeter, Target Practice .............................................................................. Table 3-1....... 3-3A675 - Cartridge, 20-Millimeter, Armor-Piercing, Discarding Sabot ................................................ Table 3-1....... 3-3A676 - Cartridge, 20-Millimeter, Armor-Piercing, Discarding Sabot ................................................ Table 3-1....... 3-3A692 - Cartridge, 20-Millimeter, Armor-Piercing, Discarding Sabot ................................................ Table 3-1....... 3-3A763 - Cartridge, 20-Millimeter, Discarding Sabot ........................................................................... Table 3-1....... 3-3A765 - Cartridge, 20-Millimeter, Armor-Piercing, Tracer ................................................................. Table 3-2....... 3-5A776 - Cartridge, 20-Millimeter, Incendiary ......................................................................................Table 3-2....... 3-5A777 - Cartridge, 20-Millimeter, Target Practice (M204) ................................................................. Table 3-3....... 3-6A777 - Cartridge, 20-Millimeter, Target Practice (M99) ................................................................... Table 3-2....... 3-5A785 - Cartridge, 20-Millimeter, High Explosive, Incendiary ........................................................... Table 3-3....... 3-6A967 - Cartridge, 25-Millimeter, Dummy .......................................................................................... Table 3-4....... 3-9A974 - Cartridge, 25-Millimeter, Armor-Piercing, Discarding Sabot, Tracer ................................... Table 3-4....... 3-9A976 - Cartridge, 25-Millimeter, Target Practice, Tracer .................................................................. Table 3-4....... 3-9A981 - Cartridge, 25-Millimeter, High Explosive, Incendiary, Tracer .............................................. Table 3-4....... 3-9AA20 - M51A4N Dummy Round ...................................................................................................... 3-2.3.1.1.4..... 3-3AA61 - Cartridge, 20MM, Armor Piercing, Discarding Sabot (M50 Series Data) ............................ Table 3-1....... 3-3AA71 - Armor-Piercing, Fin Stabilized, Discarding Sabot, Traced ................................................... Table 3-5..... 3-11AA72 - Armor-Piercing, Fin Stabilized, Discarding Sabot, Traced ................................................... Table 3-5..... 3-11AA89 - High Explosive, Incendiary Traced and Multi-Purpose Low Drag Traced Linked in 1 to 1

Ratio ....................................................................................................................................... Table 3-5..... 3-11AA90 - Target Practice, Traced .......................................................................................................... Table 3-5..... 3-11B099 - Dummy - PGU 16/A ............................................................................................................... Table 3-5..... 3-11B551 - Cartridge, 40-Millimeter, Armor-Piercing .............................................................................. Table A-1......A-8B552 - Cartridge, 40-Millimeter,, Armor-Piercing, Tracer ................................................................ Table A-1......A-8B556 - Cartridge, 40-Millimeter, High Explosive, Incendiary, Plugged ............................................ Table A-1......A-8B557 - Cartridge, 40-Millimeter, High Explosive, Incendiary, Self-Destruct ................................... Table A-1......A-8B558 - Cartridge, 40-Millimeter, High Explosive, Incendiary, Tracer, Non-Self-Destruct ............... Table A-1......A-8B559 - Cartridge, 40-Millimeter, High Explosive, Incendiary, Tracer, Self-Destruct ....................... Table A-1......A-8B560 - Cartridge, 40-Millimeter, High Explosive, Incendiary, Dark Ignition, Self-Destruct ............ Table A-1......A-8B561 - Cartridge, 40-Millimeter, High Explosive, Plugged ............................................................... Table A-1......A-8B562 - Cartridge, 40-Millimeter, High Explosive, Tracer, Self-Destruct .......................................... Table A-1......A-8B563 - Cartridge, 40-Millimeter, Blind Loaded and Plugged ............................................................ Table A-1......A-8B564 - Cartridge, 40-Millimeter, Blind Loaded and Tracer ............................................................... Table A-1......A-8B565 - Cartridge, 40-Millimeter, Dummy .......................................................................................... Table A-1......A-8BA22 - Cartridge, Target Practice (TP) round, MK 296 Mod 0 ........................................................ 3-6.2.2......... 3-18BA23 - Cartridge, Pre-fragmented, Programmable Proximity (3P) fuzed round, MK 295 Mod 0 .... 3-6.2.1......... 3-17C058 - Cartridge, 76-Millimeter, Target Practice, Variable Time, Nonfragmenting ......................... Table 3-11... 3-21C059 - Cartridge, 76-Millimeter, High Explosive, Variable Time ..................................................... Table 3-11... 3-21C060 - Cartridge, 76-Millimeter, High Explosive, Infrared ............................................................... Table 3-11... 3-21C061 - Cartridge, 76-Millimeter, High Explosive, Point Detonating ................................................. Table 3-11... 3-21

APPENDIX E

DODIC/NOMENCLATURE CURRENT INDEX

DODIC/NALC ITEM NOMENCLATURE PARAGRAPH/

TABLE NO. PAGE

SW030-AA-MMO-010

E-2

APPENDIX E (Continued)


TABLE NO. PAGE

C062 - Cartridge, 76-Millimeter, Blind Loaded and Plugged .............................................................Table 3-11 ... 3-21C066 - Cartridge, 76-Millimeter, High Explosive, Controlled Variable Time ...................................Table 3-11 ... 3-21C097 - Cartridge, 76-Millimeter, Dummy, Rammable .......................................................................Table 3-11 ... 3-21C112 - Cartridge, 76-Millimeter, High Explosive, Infrared ...............................................................Table 3-11 ... 3-21C113 - Cartridge, 76-Millimeter, High Explosive, Point Detonating .................................................Table 3-11 ... 3-21C116 - Charge, 76-Millimeter, Clearing .............................................................................................Table 3-11 ... 3-21C118 - Cartridge, 76-Millimeter, Dummy, Nonrammable .................................................................Table 3-11 ... 3-21D290 - Projectile, 5-Inch, 54 Caliber, Smoke - Point Detonating ......................................................Table 3-13 ... 3-26D291 - Projectile, 5-Inch, 54 Caliber, Smoke - Mechanical Time ......................................................Table 3-13 ... 3-26D295 - Projectile, 5-Inch, 54 Caliber, High Explosive - Controlled Variable Time ..........................Table 3-13 ... 3-26D297 - Projectile, 5 Inch, 54 Caliber, Reduced Charge, Flashless, Poly Plug ...................................3-8.2. ........... 3-24D314 - Projectile, 5-Inch, 54 Caliber, White Phosphorus - Point Detonating ....................................Table 3-13 ... 3-26D317 - Projectiile, 5-Inch, 54 Caliber .................................................................................................Table 3-13 ... 3-26D326 - Projectile, 5 Inch, 54 Caliber, Universal, Poly Plug ...............................................................3-8.2. ........... 3-24D327 - Projectile, 5-Inch, 54 Caliber, High Explosive - Infrared .......................................................Table 3-13 ... 3-26D330 - Projectile, 5-Inch, 54 Caliber, High Explosive - Point Detonating .........................................Table 3-13 ... 3-27D331 - Projectile, 5-Inch, 54 Caliber, High Explosive - Variable Time - Self Destruct ....................Table 3-13 ... 3-27D332 - Projectile, 5-Inch, 54 Caliber, High Explosive - Variable Time .............................................Table 3-13 ... 3-27D334 - Projectile, 5-Inch, 54 Caliber, Dummy ...................................................................................Table 3-13 ... 3-27D334 - Projectile, 5-Inch, 54 Caliber, Nonfragmenting - Variable Time ...........................................Table 3-13 ... 3-27D334 - Projectile, 5-Inch, 54 Caliber, Nonfragmenting - Variable Time ...........................................Table 3-13 ... 3-27D336 - Projectile, 5-Inch, 54 Caliber, Dummy ...................................................................................Table 3-13 ... 3-27D338 - Projectile, 5-Inch, 54 Caliber, High Explosive - Mechanical Time - Point Detonating .........Table 3-13 ... 3-27D339 - Projectile, 5-Inch, 54 Caliber, High Explosive - Point Detonating /Delay .............................Table 3-13 ... 3-27D340 - Projectile, 5-Inch, 54 Caliber, High Explosive - Mechanical Time/Point Detonating ...........Table 3-13 ... 3-27D341 - Projectile, 5-Inch, 54 Caliber, Blind Loaded and Plugged .....................................................Table 3-13... 3-27D346 - Projectile, 5-Inch, 54 Caliber, High Explosive - Controlled Variable Time ..........................Table 3-13 ... 3-27D349 - Projectile, 5-Inch, 54 Caliber, Blind Loaded and Plugged .....................................................Table 3-13... 3-27D350 - Projectile, 5-Inch, 54 Caliber, High Explosive - Controlled Variable Time ..........................Table 3-13 ... 3-27D351 - Projectile, 5-Inch, 54 Caliber, Smoke - Mechanical Time/Point Detonating .........................Table 3-13 ... 3-27D353 - Projectile, 5-Inch, 54 Caliber, Illuminating - Mechanical Time .............................................Table 3-13 ... 3-27D354 - Projectile, 5-Inch, 54 Caliber, Illuminating - Mechanical Time .............................................Table 3-13 ... 3-27D803 - Projectile, 5-Inch, 54 Caliber, High Explosive - Controlled Variable Time ..........................Table 3-13 ... 3-27D884 - Projectile, 5-Inch, 54 Caliber, High Explosive - Point Detonating/Delay ..............................Table 3-13 ... 3-27DA01 - Projectile, 5-Inch, 54 Caliber, Smoke - Infrared ....................................................................Table 3-13 ... 3-27DA06 - Projectile, 5-Inch, 54 Caliber, Nonfragmenting - Infrared .....................................................Table 3-13 ... 3-27DA08 - Projectile, 5-Inch, 54 Caliber, High Explosive - Multi-Function ..........................................Table 3-13 ... 3-27DA15 - Projectile, 5-Inch, 54 Caliber, Kinetic Energy - Electronic Time ..........................................Table 3-13 ... 3-27DA34 - Projectile, 5-Inch, 54 Caliber, High Explosive - Explosive Time .........................................Table 3-13 ... 3-27

SW030-AA-MMO-010

F-1

C136 - Cartridge, 3-Inch, 50-Caliber, High Explosive Variable Time, Self- Destruct ...................Table A-11......A-51C137 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Non-Self-Destruct ...........Table A-11......A-51C139 - Charge, 3-Inch, 50-Caliber, Blank Saluting ........................................................................Table A-11......A-53C140 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Self-Destruct ...................Table A-11......A-51C141 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Non-Self-Destruct ...........Table A-11......A-51C143 - Cartridge, 3-Inch, 50-Caliber, Armor-Piercing ...................................................................Table A-11......A-52C150 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Non-Self-Destruct ...........Table A-11......A-51C151 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Non-Self-Destruct ...........Table A-11......A-51C151 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Non-Self-Destruct ...........Table A-11......A-51C152 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Non-Self-Destruct ...........Table A-11......A-51C153 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Self-Destruct ...................Table A-11......A-51C162 - Cartridge, 3-Inch, 50-Caliber, Target Practice, Nonfragmenting, Variable Time,

Self-Destruct ........................................................................................................................Table A-11......A-52C164 - Cartridge, 3-Inch, 50-Caliber, Target Practice, Nonfragmenting, Variable Time,

Non-Self-Destruct ................................................................................................................Table A-11......A-52C178 - Cartridge, 3-Inch, 50-Caliber, Blind Loaded and Plugged ..................................................Table A-11......A-53C179 - Cartridge, 3-Inch, 50-Caliber, Blind Loaded and Plugged ..................................................Table A-11......A-53C183 - Charge, 3-Inch, 50-Caliber, Blank Saluting ........................................................................Table A-11......A-53C184 - Charge, 3-Inch 50-Caliber, Short Clearing ..........................................................................Table A-11......A-53C207 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Self-Destruct ...................Table A-11......A-51C208 - Cartridge, 3-Inch, 50-Caliber, Variable Time, Non-Self-Destruct ......................................Table A-11......A-51C212 - Cartridge, 3-Inch, 50-Caliber, Armor-Piercing ...................................................................Table A-11......A-52C215 - Cartridge, 3-Inch, 50-Caliber, Armor-Piercing ...................................................................Table A-11......A-52C218 - Cartridge, 3-Inch, 50-Caliber, High Capacity......................................................................Table A-11......A-52C296 - Cartridge, 3-Inch, 50-Caliber, High Capacity......................................................................Table A-11......A-52C299 - Cartridge, 3-Inch, 50-Caliber, Antiaircraft ..........................................................................Table A-11......A-52C302 - Cartridge, 3-Inch, 50-Caliber, Antiaircraft ..........................................................................Table A-11......A-52C305 - Cartridge, 3-Inch, 50-Caliber, Illuminating .........................................................................Table A-11......A-52C306 - High Explosive, Infrared......................................................................................................Table A-11......A-52C307 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Infrared .....................................................Table A-11......A-52C319 - Cartridge, 3-Inch, 50-Caliber, Target Practice, Nonfragmenting, Variable Time,

Self-Destruct........................................................................................................................Table A-11......A-52C320 - Cartridge, 3-Inch, 50-Caliber, Target Practice, Nonfragmenting, Variable Time,

Non-Self-Destruct ...............................................................................................................Table A-11......A-52C321 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Infrared .....................................................Table A-11......A-52C322 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Infrared .....................................................Table A-11......A-52C338 - Cartridge, 3-Inch, 50-Caliber, Blind Loaded and Plugged ..................................................Table A-11......A-53C341 - Cartridge, 3-Inch, 50-Caliber, Blind Loaded and Plugged ..................................................Table A-11......A-53C347 - Cartridge, 3-Inch, 50-Caliber, High Capacity......................................................................Table A-11......A-52


TABLE NO. PAGE

APPENDIX F

DODIC/NOMENCLATURE HISTORICAL INDEX

SW030-AA-MMO-010

F-2

APPENDIX F (Continued)


TABLE NO. PAGE

C348 - Cartridge, 3-Inch, 50-Caliber, High Capacity ..................................................................... Table A-11 ..... A-52C349 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Point Detonating ...................................... Table A-11 ..... A-52C355 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Self-Destruct................... Table A-11 ..... A-51C356 - Cartridge, 3-Inch, 50-Caliber, High Explosive, Variable Time, Non-Self-Destruct .......... Table A-11 ..... A-51C373 - Cartridge, 3-Inch, 50-Caliber, Target Practice, Nonfragmenting, Variable Time,

Self-Destruct ....................................................................................................................... Table A-11 ..... A-52C375 - Cartridge, 3-Inch, 50-Caliber, Target Practice, Nonfragmenting, Variable Time,

Non-Self-Destruct............................................................................................................... Table A-11 ..... A-53D217 - Projectile, 5-Inch, 38-Caliber, Antiaircraft, Common, Mechanical Time .......................... Table A-2 ....... A-16D220 - Projectile, 5-Inch, 38-Caliber, Target Practice (Puff), Point Detonating............................ Table A-2 ....... A-17D221 - Projectile, 5-Inch, 38-Caliber, Target Practice (Puff), Mechanical Time........................... Table A-2 ....... A-17D225 - Projectile, 5-Inch, 38-Caliber, High Explosive, Controlled Variable Time ....................... Table A-2 ....... A-15D226 - Projectile, 5-Inch, 38-Caliber, High Explosive, Variable Time, Self-Destruct .................. Table A-2 ....... A-15D227 - Projectile, 5-Inch, 38-Caliber, Clearing .............................................................................. Table A-3 ....... A-24D228 - Projectile, 5-Inch, 38-Caliber, High Explosive, Variable Time, Non-Self-Destruct .......... Table A-2 ....... A-15D230 - Projectile, 5-Inch, 38-Caliber, Antiaircraft, Common Mechanical Time ........................... Table A-2 ....... A-16D232 - Projectile, 5-Inch, 38-Caliber, High Explosive, Variable Time, Self-Destruct .................. Table A-2 ....... A-15D233 - Projectile, 5-Inch, 38-Caliber, High Explosive, Variable Time, Non-Self-Destruct .......... Table A-2 ....... A-16D235 - Projectile, 5-Inch, 38-Caliber, High Capacity, Point Detonating ....................................... Table A-2 ....... A-16D237 - Projectile, 5-Inch, 38-Caliber, Common, Base Detonating ................................................ Table A-2 ....... A-16D238 - Projectile, 5-Inch, 38-Caliber, High Explosive, Point Detonating...................................... Table A-2 ....... A-15D241 - Projectile, 5-Inch, 38-Caliber, High Explosive, Mechanical Time..................................... Table A-2 ....... A-15D242 - Projectile, 5-Inch, 38-Caliber, High Capacity, Base Detonating ........................................ Table A-2 ....... A-16D243 - Projectile, 5-Inch, 38-Caliber, High Explosive, Mechanical Time..................................... Table A-2 ....... A-15D244 - Projectile, 5-Inch, 38-Caliber, Illuminating, Mechanical Time.......................................... Table A-2 ....... A-16D245 - Projectile, 5-Inch, 38-Caliber, High Explosive, Point Detonating...................................... Table A-2 ....... A-15D246 - Projectile, 5-Inch, 38-Caliber, White Phosphorus (Smoke), Point Detonating .................. Table A-2 ....... A-17D247 - Projectile, 5-Inch, 38-Caliber, White Phosphorus (Smoke), Mechanical Time ................. Table A-2 ....... A-17D248 - Projectile, 5-Inch, 38-Caliber, Target Practice, Nonfragmenting, Variable Time,

Self-Destruct........................................................................................................................ Table A-2 ....... A-17D249 - Projectile, 5-Inch, 38-Caliber, Target Practice, Nonfragmenting, Variable Time,

Self-Destruct........................................................................................................................ Table A-2 ....... A-17D250 - Projectile, 5-Inch, 38-Caliber, Target Practice, Nonfragmenting, Variable Time,

Non-Self-Destruct ............................................................................................................... Table A-2 ....... A-17D251 - Projectile, 5-Inch, 38-Caliber, Target Practice, Nonfragmenting, Variable Time,

Non-Self-Destruct ............................................................................................................... Table A-2 ....... A-17D252 - Projectile, 5-Inch, 38-Caliber, Dummy............................................................................... Table A-2 ....... A-18D255 - Projectile, 5-Inch, 38-Caliber, Illuminating, Mechanical Time.......................................... Table A-2 ....... A-16D256 - Projectile, 5-Inch, 38-Caliber, Illuminating, Mechanical Time, Point Detonating............. Table A-2 ....... A-16D260 - Projectile, 5-Inch, 38-Caliber, Rocket Assisted, Controlled Variable Time....................... Table A-2 ....... A-16D261 - Projectile, 5-Inch, 38-Caliber, Rocket Assisted, Controlled Variable Time....................... Table A-2 ....... A-16

F-3/(F-4 blank)

SW030-AA-MMO-010


TABLE NO. PAGE

APPENDIX F (Continued)

D262 - Projectile, 5-Inch, 38-Caliber, Rocket Assisted, Controlled Variable Time....................... Table A-2 ....... A-16D263 - Projectile, 5-Inch, 38-Caliber, Dummy............................................................................... Table A-2 ....... A-18D264 - Charge, 5-Inch, 38-Caliber, Propelling, Full ...................................................................... A-3.3.2. .......... A-14D267 - Projectile, 5-Inch, 38-Caliber, Blind Loaded and Plugged, Inert ....................................... Table A-2 ....... A-18D272 - Charge, 5-Inch, 38-Caliber, Propelling, Full ...................................................................... A-3.3.2. .......... A-14D274 - Charge, 5-Inch, 38-Caliber, Propelling, Full ...................................................................... A-3.3.2. .......... A-14D280 - Projectile, 5-Inch, 38-Caliber, High Explosive, Self-Destruct ........................................... Table A-2 ....... A-15D281 - Projectile, 5-Inch, 38-Caliber, White Phosphorus (Smoke), Mechanical Time ................. Table A-2 ....... A-17D282 - Charge, 5-Inch, 38-Caliber, Propelling, Reduced............................................................... A-3.3.2. .......... A-14D282 - Charge, 5-Inch, 38-Caliber, Propelling, Reduced............................................................... Table A-3 ....... A-24D286 - Projectile, 5-Inch, 38-Caliber, Chaff Dispensing, Mechanical Time.................................. Table A-2 ....... A-18D287 - Projectile, 5-Inch, 38-Caliber, Chaff Dispensing, Mechanical Time.................................. Table A-2 ....... A-18D292 - Projectile, 5-Inch, 38-Caliber, High Explosive, Mechanical Time, Point Detonating ....... Table A-2 ....... A-15D298 - Projectile, 5-Inch, 38-Caliber, White Phosphorus (Smoke)................................................ Table A-2 ....... A-17D306 - Charge, 5-Inch, 38-Caliber, Clearing.................................................................................. Table A-3 ....... A-24D324 - Charge, 5-Inch, 54 Caliber, Propelling, Full....................................................................... 2-4.11.5. ............ 2-9D460 - Projectile, 5-Inch, 38-Caliber, Target Practice (Puff), Mechanical Time, Point DetonatingTable A-2 ...... A-17D839 - Charge, 16-Inch, 50-Caliber, Propelling, Full .................................................................... Table A-9 ....... A-40D840 - Charge, 16-Inch, 50-Caliber, Propelling, Reduced............................................................. Table A-9 ....... A-40D844 - Charge, 16-Inch, 50-Caliber, Dummy ................................................................................ Table A-9 ....... A-40D845 - Charge, 16-Inch, 50-Caliber, Propelling, Reduced............................................................. Table A-9 ....... A-40D846 - Charge, 16-Inch, 50-Caliber, Propelling, Full .................................................................... Table A-9 ....... A-40D862 - Projectile, 16-Inch, 50-Caliber, Armor-Piercing ................................................................ Table A-8 ....... A-36D872 - Projectile, 16-Inch, 50-Caliber, Armor-Piercing ................................................................ Table A-8 ....... A-36D873 - Projectile, 16-Inch, 50-Caliber, Blind Loaded and Plugged ............................................... Table A-8 ....... A-37D877 - Projectile, 16-Inch, 50-Caliber, High Capacity, Controlled Variable Time ....................... Table A-8 ....... A-37D878 - Projectile, 16-Inch, 50-Caliber, Base Detonating ............................................................... Table A-8 ....... A-36D879 - Projectile, 16-Inch, 50-Caliber, High Capacity, Special..................................................... Table A-8 ....... A-36D880 - Projectile, 16-Inch, 50-Caliber, High Capacity, Mechanical Time & Base Detonating..... Table A-8 ....... A-36D881 - Projectile, 16-Inch, 50-Caliber, Blind Loaded and Plugged, Tracer................................... Table A-8 ....... A-37D882 - Projectile, 16-Inch, 50-Caliber, High Capacity, Point Detonating ..................................... Table A-8 ....... A-36DW40 - Cartridge, 5-Inch, 38-Caliber, Test ................................................................................... Table A-3 ....... A-24

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NAVSEA SW030-AA-MMO-010 SIXTH REVISION

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