1

CO

NT

RA

CT

NU

MB

ER

N00164-94-C

-0040SW370-BD-OPI-010

Operator’s ManualMark 23 Pistol, Semi-automatic,

Caliber .45 ACP

© H

eckler & K

och, Inc., October 1996

21480 Pacific B

lvd.S

terling, Virginia 20166-8903

United S

tates of Am

ericaT

elephone (703) 450-1900 ®

WARNING

A firearm has the capability of taking your life or the life of someone else! Be extremely careful with your

firearm. An accident can occur at anytime and is almost always the result of not following basic safety rules.

2

TABLE OF CONTENTS

PA

GE

CH

AP

TE

R 1

INT

RO

DU

CT

ION

.....................................................................................................................................................4

SE

CT

ION

IG

EN

ER

AL IN

FO

RM

AT

ION

........................................................................................................................................4S

EC

TIO

N II

PIS

TO

L DE

SC

RIP

TIO

N............................................................................................................................................6

1.2 Nom

enclature................................................................................................................................6

1.3 Principle of O

peration..................................................................................................................

71.4 M

ajor Assem

bly Groups

...............................................................................................................7

1.5 Technical S

pecifications...............................................................................................................9

CH

AP

TE

R 2

OP

ER

AT

ING

INS

TR

UC

TIO

NS

.............................................................................................................................10

SE

CT

ION

IS

ER

VIC

E U

PO

N R

EC

EIP

T O

F M

AT

ER

IAL

...........................................................................................................10

2.1 Initial Inspection.........................................................................................................................

10S

EC

TIO

N II

GE

NE

RA

L DE

SC

RIP

TIO

N....................................................................................................................................

102.2 D

escription..................................................................................................................................

102.3 O

peration and Characteristics

...................................................................................................11

2.4 Cycle of O

peration.....................................................................................................................

132.5 S

afety Features

..........................................................................................................................17

SE

CT

ION

IIIO

PE

RA

TIO

N U

ND

ER

NO

RM

AL C

ON

DIT

ION

S..................................................................................................

182.6 C

learing Procedures

..................................................................................................................18

2.7 Loading and Unloading the M

agazine.......................................................................................

192.8 Loading P

rocedure.....................................................................................................................

202.9 R

eadying the Pistol for F

iring....................................................................................................

212.10 F

iring the Pistol

........................................................................................................................22

SE

CT

ION

IVO

PE

RA

TIO

N U

ND

ER

UN

US

UA

L CO

ND

ITIO

NS

................................................................................................23

2.11 Extrem

e Cold

............................................................................................................................23

2.12 Hot, W

et Clim

ates....................................................................................................................

232.13 H

ot, Dry C

limates

.....................................................................................................................24

2.14 Heavy R

ain and Water O

perations - All C

limates

...................................................................24

3

SE

CT

ION

VM

ALF

UN

CT

ION

S A

ND

ST

OP

PA

GE

S..................................................................................................................

252.15 R

emedial A

ction........................................................................................................................

25C

HA

PT

ER

3M

AIN

TE

NA

NC

E IN

ST

RU

CT

ION

S.......................................................................................................................

27S

EC

TIO

N I

TO

OLS

& E

QU

IPM

EN

T..........................................................................................................................................

273.1 O

perator Tools and E

quipment R

equired..................................................................................

27S

EC

TIO

N II

PM

S C

HE

CK

S &

MA

INT

EN

AN

CE

PR

OC

ED

UR

ES

..............................................................................................27

3.2 General.......................................................................................................................................

273.3 D

isassembly (F

ield stripping).....................................................................................................28

3.4 Reassem

bly (From

field strip)....................................................................................................30

3.5 Safety/F

unction Check

...............................................................................................................33

3.6 Function F

iring............................................................................................................................

363.7 C

leaning.....................................................................................................................................

363.8 Inspection

...................................................................................................................................37

3.9 Lubrication..................................................................................................................................

38S

EC

TIO

N III

AD

JUS

TM

EN

T O

F S

IGH

TS

.................................................................................................................................40

SE

CT

ION

IVT

RO

UB

LES

HO

OT

ING

PR

OC

ED

UR

ES

...............................................................................................................43

3.10 Operator T

roubleshooting Procedures

....................................................................................43

3.11 Parts Listing and E

xploded Diagram

.......................................................................................46

CH

AP

TE

R 4

AM

MU

NIT

ION

.......................................................................................................................................................48

FIR

EA

RM

SE

RV

ICE

RE

CO

RD

...................................................................................................................INS

IDE

BA

CK

CO

VE

R

4

CHAPTER 1 INTRODUCTION

SECTION I - GENERAL INFORMATION

The H

K M

ark 23 .45 AC

P pistol give shooters m

atchgrade accuracy equal to that of the finest custom

made

handguns — yet it exceeds the m

ost stringent operationalrequirem

ents ever demanded of a com

bat handgun.

The M

ark 23 provides this accuracy without the need for

hand-fitted parts comm

on in custom-built m

atch pistolscosting thousands of dollars m

ore. Repair of the M

ark 23is reduced to a sim

ple parts exchange.

The H

K M

ark 23, is a comm

ercial model of the U

.S.

Governm

ent issue MK

23, MO

D 0 pistol and is available

in limited num

bers. Designated the “M

ark 23”, it is almost

identical to the MK

23, MO

D 0 pistol used by the S

pecialO

perations Com

mand, right dow

n to its threaded barrel.T

he main differences are slide M

arkings (Mark 23 as

opposed to MK

23) and a barrel manufactured to S

AM

MI

headspace specifications.

One of the m

ost thoroughly tested handguns in history,the M

K23/M

ark 23 project originated in 1991 when H

Kw

as awarded a developm

ent contract for the Special

Operations F

orces Offensive H

andgun Weapon S

ystem,

consisting of a caliber .45 pistol, detachable sound andflash suppressor, and laser aim

ing module (LA

M).

During testing, M

K 23 pistols m

et the most stringent

operational and accuracy requirements ever dem

anded ofa com

bat handgun. MK

23 pistols achieved match grade

accuracy of less than a 2.5 inch maxim

um extrem

espread in 5-round shot groups at 25 m

eters with service

amm

unition. Endurance testing dem

onstrated a servicelife of over 30,000 rounds of +

P am

munition w

ith no partsbreakage, w

ith an additional 30,000 rounds certified onthe slide and fram

e.

To m

eet the reliability requirement, the pistol had to

demonstrate a m

inimum

of 2,000 mean rounds betw

eenstoppages (M

RB

S) w

ith both M1911 ball and +

Pam

munition. T

he minim

um M

RB

S achieved in testing w

as6,027 and the m

aximum

was 15,122!

During over 450 accuracy test firings from

a precisionfiring fixture, M

K 23 pistols far exceeded the governm

entrequirem

ent, averaging 1.44 inches, with 65 groups of

less than one inch. There w

ere four groups of .5 inches,w

ith 5 rounds going through the same hole! T

his includedfiring w

ith and without the sound/flash suppressor

attached.

5

Three pistols w

ere tested for accuracy after firing over30,000 rounds, the specified service life of the pistol, andstill m

et the new pistol accuracy requirem

ent. An

innovative design feature, a high temperature rubber O

-ring on the barrel that seals the barrel in the slide untilunlocking, led to this rem

arkable achievement. T

he O-ring

lasts beyond 20,000 rounds and can be replaced by theoperator w

ithout tools in seconds.

To m

eet operational environmental requirem

ents, thepistol w

as function tested at +140 and -25

0 F, im

mersed in

salt water, exposed to surf, salt-fog, sand-dust, m

ud,icing, unlubricated, and a variety of other fouledenvironm

ents. A special m

aritime surface coating protects

the pistol from corrosion, in all of these operational

environments.

The barrel is threaded to accept accessories such as a

flash and sound suppressor. The unique H

K polygonal

bore profile increases muzzle velocity and service life,

reduces bore fouling and eases cleaning.

The fram

e mounted M

K 23 decocking lever is separate

from the am

bidextrous safety lever. It allows the ham

mer

to be lowered quietly and safely from

the single actionposition. W

hen the hamm

er is down, the am

bidextrousfram

e mounted safety lever is locked in the fire position

so that the pistol is always ready for double action

operation. When the ham

mer is “cocked and locked” in

single action mode w

ith the safety lever on “safe”, thedecocker is blocked so that the pistol is alw

ays ready forsingle action operation. E

ven with the safety lever

engaged, the slide can still be manipulated to load and

clear the pistol.

The extended slide release lever and the am

bidextrousm

agazine release are easily operated without adjustm

entof the firing grip using the firing hand thum

b or indexfinger.

Other notable features include accessory m

ountinggrooves on the fram

e, a mechanical recoil reduction

system that reduces recoil forces to the shooter and

components of the pistol by as m

uch as 30%, a polym

erfram

e, a one-piece machined steel slide, and a law

enforcement/m

ilitary magazine capacity of tw

elve rounds.T

he weapon is aim

ed using either iron sights or anoptional laser aim

ing component. T

he iron sights providea 3-dot sight picture w

ith white or optional self-lum

inoustritium

dots.

The M

K 23 becam

e the first caliber .45 AC

P pistol to

enter U.S

. military service since the venerable

Governm

ent Model 1911A

1. On M

ay 1, 1996, the first MK

23 pistols were delivered to the U

.S. S

pecial Operations

Com

mand for operational deploym

ent.

6

SECTION II - PISTOL DESCRIPTION

1.2 No

men

clatureF

igure 1 Left View

1.3 Prin

ciple o

f Op

eration

A. T

he Mark 23 uses a m

odified linkless Brow

ning-style short recoil system

to lock and unlock thebreech.

Figure 2 R

ight View

B. U

pon firing, the pressure developed by thepropellent gas forces the slide and barrelassem

bly to the rear. After approxim

ately 3 mm

,the locking block w

ill stop the rearward

movem

ent of the barrel as the barrel is pivoteddow

nward due to the engagem

ent of the angledsurfaces of the locking block w

ith those located

rear sight

rightsafety lever

extractorbarrel locking

block

front sightejection

port

accessorym

ountinggroove

slide releaseaxle recess

trigger

magazine

release

lanyard loop

sliderecess for slide

release/stop

slide releasemagazine

frame

accessorym

ountinggroove

magazine

release

decockinglever

left safetylever

threaded insertfor accessory locking

flaredtrigger guard

hamm

erthreaded barrel

7

in the recoil spring guide rod. The locking block

will disengage from

the slide and the slide will

continue rearward.

The extractor located in the slide w

ill thenextract the fired cartridge case, the ejectorlocated in the fram

e on the left side of them

agazine well w

ill eject the fired case as theslide continues rearw

ard and cocks theham

mer, and com

presses the recoil spring.

The slide m

oves forward feeding the next

cartridge from the m

agazine into the chamber

and locking to the barrel breech.

C. T

he slide locks open after the last round hasbeen fired and ejected.

WARNING

Do not rely on the slide lock to determine if

the magazine is empty. Always check visually

and physically ensure the pistol is not loaded.

1.4 Majo

r Assem

bly G

rou

ps (S

ee Figure 3)

A. S

lide - houses the firing pin, firing pin block and

extractor; cocks hamm

er during recoil.

B. C

aptu

red R

ecoil/B

uffer S

prin

g A

ssemb

ly(w

ith g

uid

e rod

) - absorbs recoil and returnsthe slide and barrel to their forw

ard positions;reduces im

pact of slide on receiver duringrecoil. T

he recoil spring is “captured” by a C-clip

on the end of the guide rod.

C. T

hread

ed B

arrel (with

lockin

g b

lock) -

contains cartridge and propellent gases duringfiring. T

he locking block initiates locking andunlocking of the breech during m

ovement of

slide. The O

-ring holds the barrel tight in theslide until unlocking.

D. F

rame - serves as support to all m

ajorcom

ponents; controls functioning of pistol. The

slide release locks the slide with barrel and

recoil/buffer spring assembly to the m

etallocking insert cast into the synthetic fram

e. Alanyard loop is in the bottom

of the grip forattaching a lanyard. T

he trigger guard is flaredon both sides to preclude accidental actuationof the m

agazine release during holstering.

8

E. M

agazin

e - holds the cartridges in position forfeeding and cham

bering.F

. Slid

e Release - holds slide to rear w

henengaged; releases slide w

hen lever isdepressed.

Figure 3 M

ajor Assem

bly Groups

A. S

lide

C. T

hread

edB

arrel

D. F

rame

E. M

agazin

e

F. S

lide R

elease

accessorym

ounting groovethreaded insert foraccessory locking

O-ring

threads

barrel locking block

flared trigger guard

lanyard loop insert

C-clip

guide rod

recoil springbuffer spring

B. C

aptu

red R

ecoil/B

uffer

Sp

ring

Assem

bly

safety

magazine

release

decocker

9

1.5 Technical Specifications:

Caliber

.45 AC

P (A

utomatic C

olt Pistol)

System

of Operation

short recoil, semi-autom

aticLocking S

ystemB

rowning system

(modified), linkless

LengthB

arrel5.87 in.

(149 mm

)S

ight radius7.76 in.

(197 mm

)P

istol9.65 in.

(245 mm

)

Weight

Magazine (em

pty) 12 or 10 rd. capacity.24 lbs.

(.110 kg)M

agazine (w/12 rds M

1911 Ball)

.81 lbs.(.366 kg)

Magazine (w

/10 rds M1911 B

all).72 lbs.

(.327 kg)P

istol (w/ em

pty 12 or 10 rd magazine)

2.66 lbs.(1.21 kg)

Pistol (w

/ 12 rds M1911 B

all)3.22 lbs.

(1.46 kg)P

istol (w/ 10 rds M

1911 Ball)

3.13 lbs.(1.42 kg)

Trigger P

ullS

ingle-action4.85 lbs.

(2.20 kg)D

ouble-action12.13 lbs.

(5.50 kg)

Height

5.90 in.(150 m

m)

Width

1.53 in.(38.8 m

m)

Muzzle velocity

M1911 230 grain ball

886 fps(270 m

/s)+

P 185 grain JH

P1142 fps

(348 m/s)

Maxim

um E

ffective Range

54.7 yds(50 m

)M

aximum

Range (M

1911 ball)1,467 yds

(1,341 m)

Rifling

polygonal bore right hand twist

Magazine

staggered, 12 round capacity (10 round civilian)

Safety F

eatures1. safety lever (m

anual), 2. double-action mode w

ith 12.1 lb. triggerpull, 3. firing pin block, 4. disconnector

10

SECTION II - GENERAL DESCRIPTION

2.2 Descrip

tion

: The M

ark 23 is a semiautom

atic,m

agazine fed, recoil operated, double/single-actionpistol, cham

bered for the .45 AC

P cartridge up to,

and including, the comm

ercial +P

cartridges.

WARNING

The Mark 23 incorporates single and double

action modes of operation. Anytime the trig-

ger is pulled with the safety lever in the fire

(down) position and a round in the chamber,

the pistol will fire from either the hammer

down (DA) or cocked position (SA).

CHAPTER 2 OPERATING INSTRUCTIONS

SECTION I - SERVICE UPON RECEIPT OF MATERIAL

2.1 Initial In

spectio

n. U

pon initial receipt, the pistolis to be inspected to ensure it w

as received inproper w

orking order.

Step

Actio

nR

eference

1R

emove pistol and item

sfrom

container2

Rem

ove packing material

3C

heck for missing item

s4

Field strip w

eapon andinspect for:

para. 3.3 M

issing parts P

roper assembly

5C

lean, dry and lubricate (if necessary)

para. 3.7, 3.96

Assem

blepara. 3.4

7S

afety/ function checkpara. 3.5

11

CAUTION

A pair of Universal Mounting Grooves located

on the front of the Mark 23 frame allow for a

variety of accessories to be used with the

pistol. Improperly designed or installed

accessories may result in damage to the

Mark 23 mounting grooves and/or the Mark

23. Such damage is not covered under

warranty. Be certain to use only HK Authorized

Accessories and follow installation and

precautions carefully.

NOTE

Accessories designed for the Universal Self-

loading Pistol (USP) will not work on the

Universal Mounting Grooves of the Mark 23.

2.3 Op

eration

and

Ch

aracteristics

A. D

ou

ble/S

ing

le Actio

n - F

or double-action(D

A), pulling the trigger w

ill cock the hamm

erand im

mediately release it discharging a

chambered round. T

o fire the first chambered

round in single-action (SA

), the hamm

er must

be manually cocked before pulling the trigger.

All shots after the first one w

ill be fired single-action because the slide autom

atically recocksthe ham

mer after each shot.

B. M

agazin

e - The m

agazine is produced fromsheet steel and has a total capacity of 12rounds. T

he rounds are positioned within the

magazine in a staggered arrangem

ent. Rounds

are visible through the viewing holes located

along the back side of the magazine housing.

The view

ing holes are marked w

ith numerals

denoting the number of rounds rem

aining within.

The floor plate can be easily rem

oved fordisassem

bly and cleaning of the magazine

components.

C. L

oad

ed C

ham

ber In

dicato

r - The M

ark 23pistol does not have a loaded cham

berindicator. T

he extractor does not act as aloaded cham

ber indicator.

D. D

ecockin

g L

ever - The decocking lever allow

sthe operator to quietly low

er the cocked hamm

erw

ithout concern of an accidental discharge.W

hen the hamm

er is cocked, it may be low

ered

12

safely by moving the decocking lever fully into

the decocking (down) position. T

he decockinglever cannot be depressed (and therefore doesnot allow

the hamm

er to be lowered) if the

safety lever is engaged. The decocking lever

always springs back into its disengaged (up)

position due to the spring pressure exerted bythe decocking spring.

E. S

afety Lever - T

he safety lever is anam

bidextrous “thumb” lever located on the rear

of the frame. It is actuated by the firing thum

b ofthe operator. T

he safety lever blocks therelease of the cocked ham

mer w

hen it is in theengaged (up) “safe” position (S

ee Figure 4a).

The safety lever is depressed dow

nward into

the “fire” position (See F

igure 4b). The safety

lever is not spring actuated and therefore must

be moved m

anually from one position to the

other by the operator.

Figure 4a “S

afe” Position F

igure 4b “Fire” P

ositionT

he safety lever cannot be placed in the “safe” (up)position if the ham

mer is uncocked (dow

n).

WARNING

The pistol should always be carried with the

safety lever engaged when carried in the

single action mode. While there is a spring

detent to prevent this, the safety lever can be

moved to the “fire” position (down) with a

minimum amount of force. This could happen

during careless handling or during removal

of the pistol from the holster. Always check

the position of the safety lever during

handling.

left safety lever

hamm

er

white dot

left safety lever

red dot

hamm

er

13

F. F

rame

- The front and back straps of the

fiberglass reinforced polymer fram

e arecheckered to ensure a firm

grip, even with w

ethands or under conditions of rapid fire. T

hetrigger guard is extended, recurved and groovedto provide a firm

grip when using tw

o hands orgloves. T

he bottom of the trigger guard is flared

on both sides in front of the magazine release

lever to shield the lever from accidental

actuation.

A threaded insert is m

olded into the front face ofthe trigger guard and the fram

e is groovedforw

ard of the trigger guard for attachment of an

accessory such as a laser aiming device or an

illuminator. T

he frame is a one-piece m

oldedcom

ponent with m

etal inserts (locking insert andguiding part) cast into the fram

e duringproduction. T

he slide rides on these metal

inserts during operation.

G. S

lide R

elease Lever - T

his lever is used to lockthe slide open and for disassem

bling thew

eapon. As a slide stop, it is depressed upw

ardby the m

agazine follower or the operator’s

finger as the slide travels rearward during recoil

or manual operation. T

he slide release leverengages the recess visible on the left side of theslide and is spring actuated. T

he slide releasespring holds the slide release lever in adisengaged (dow

n) position until required. As a

disassembly lever, the slide release lever is

removed from

the left side of the frame w

henthe slide is held rearw

ard (see para. 3.3). The

slide release lever can be actuated by the firingthum

b of the right handed operator or the indexfinger of the left handed operator.

H. M

agazin

e Release L

ever - This am

bidextrous,spring actuated lever holds the m

agazine within

the grip by engaging in the notch found in theupper third of the m

agazine housing.D

epressing this lever with the firing hand index

finger or thumb w

ill allow the m

agazine to dropfrom

the grip. The m

agazine release lever isshielded from

accidental actuation by the flaredtrigger guard and the design of the syntheticfram

e surrounding the lever.

2.4 Cycle o

f Op

eration

. Begins w

ith weapon

loaded, hamm

er cocked, safety lever disengaged.

14

Figure 5 F

iring

A. F

iring

- (See F

igure 5) Pulling the trigger

rearward pulls the trigger bar forw

ard. The

trigger bar pivots the sear actuator upwards

which disengages the firing pin block. A

t thesam

e mom

ent, the sear is pivoted out ofengagem

ent from the low

er of the two shelves

located on the hamm

er. The com

pressedham

mer spring drives the ham

mer forw

ard into

the rear end of the firing pin. The firing pin

strikes the primer of the cham

bered round. The

propellent is ignited by the primer and propellent

gases are created inside the cartridge case.T

he propellent gases drive the projectile down

the polygonal bore which spins the projectile in

a clockwise direction as a m

eans to stabilize theprojectile’s flight.

B. U

nlo

cking

- (See F

igure 6) The gas pressure

and energy produced by the propellent gasespush rearw

ard on the slide, which is locked to

the barrel by the engagement of the barrel

locking block within the ejection port m

illed intothe slide. T

he opposing angled locking surfacesincorporated into the design of the barrel lockingblock and recoil spring guide rod cause the rearof the barrel to tilt dow

nward as the slide m

ovesrearw

ard. By the tim

e the slide and barrel haverecoiled approxim

ately 5 mm

, the projectile hasleft the barrel and the gas pressure w

ithin thecham

ber has dropped to a safe level. The barrel

locking block then disengages from the slide.

The slide is now

free to recoil rearward

independently of the barrel.

barrel locking block (locked)ham

mer

opposing angledlocking surfaces

firing pin

fifi

15

Figure 7 E

jection

E. C

ockin

g - (S

ee Figure 7) - A

s the slidecontinues rearw

ard the recoil impulse is

dampened by the buffer spring. T

he recoilspring is com

pressed and the hamm

errecocked.

Figure 6 U

nlocking

C. E

xtraction

-The em

pty cartridge case is heldfirm

ly against the face of the slide by the claw of

the extractor as the slide recoils rearward.

D. E

jection

- (See F

igure 7) -The rim

of thecartridge case strikes the stationary ejector. T

heem

pty case is ejected from the open ejection

port.

barrel locking block(unlocked)

recoil springguide rod

opposing angledlocking surfaces

ejection portfifi

slidecartridge

case

recoil spring

ejection portslide

hamm

er

ejector

fi fifi

16

Figure 8 F

eeding

H. L

ockin

g - (S

ee Figure 5) -T

he slide presses thebarrel forw

ard. As it does, the opposing angled

surfaces of the barrel locking block and recoilspring guide rod pivot the rear end of the barrelup into engagem

ent with the ejection port in the

slide. The slide is now

fully forward and the

new round is ready to be fired.

F. F

eedin

g - (S

ee Figure 8) -T

he compressed

recoil spring drives the slide forward. If the

magazine is em

pty, the magazine follow

er will

lift the slide release to a point where it w

ill stopthe forw

ard progress of the slide. If them

agazine is not empty, the face of the slide w

illm

ake contact with the top round in the

magazine. T

he round will be driven from

them

agazine towards the cham

ber. The tip of the

projectile is guided into the chamber by the

magazine lips until the round clears the

magazine com

pletely. At that m

oment the claw

of the extractor snaps onto the rim of the

cartridge case as it becomes parallel w

ith thebore.

G. C

ham

berin

g - T

he slide pushes the cartridgeforw

ard until the projectile enters the mouth of

the forcing cone of the bore and the face of theslide contacts the rear of the barrel lockingblock.

barrel locking block

slide face

slide

recoil spring

chamber

fi fifi

17

2.5 Safety F

eatures

A. S

afety Lever - This safety blocks the release of the

cocked hamm

er in the SA

mode. T

he safety leveris an external, m

anually operated, ambidextrous

“thumb” lever located on the left and the right side

of the frame further m

ost back from the trigger. T

hesafety lever m

ust be manually actuated by the

operator. The shaft of the safety lever m

oves thesear block into a position w

here it blocks them

ovement of the sear actuator. T

he sear actuator,in turn, does not allow

the sear to pivot forward and

thus the hamm

er cannot be released. Engaging the

safety lever also interrupts the function of thedecocking lever and blocks the ham

mer

mechanically. T

he safety lever does not restrict them

ovement of the slide. T

he safety lever is held ineither the fire or safe position by a spring detent.T

he safety lever cannot be placed in the safe (up)position w

hen the hamm

er is down (uncocked).

B. D

ou

ble-A

ction

Mo

de - T

his safety keeps theham

mer in an uncocked condition until the

mom

ent of firing. The double-action m

odeoperates as a passive safety feature in thepistol m

uch as this mode of operation w

ould in

any DA

revolver or pistol. The ham

mer is left

uncocked until the decision to fire is made. A

t alltim

es the firing pin is locked by the firing pinblock until the trigger is pulled. A

pproximately

12.1 pounds of pressure on the trigger isrequired to cock and release the ham

mer in the

DA

mode of operation. T

he mode of operation

also permits subsequent ham

mer strikes on the

same cham

bered round by simply resqueezing

the trigger.

C. F

iring

Pin

Blo

ck - This safety prevents the

firing pin from striking the prim

er when the

weapon is dropped, the ham

mer is bum

ped, orw

hen the slide slams forw

ard. The firing pin

block is located in the slide and blocks theforw

ard movem

ent of the firing pin. Only w

henthe trigger is depressed can the sear actuatorpush the firing pin block upw

ard against thedow

nward pressure exerted by the firing pin

block spring. Once the round has been fired and

the slide begins to recoil, the firing pin block ispushed back dow

n by the firing pin block springand engages w

ithin the recess provided in thecenter portion of the firing pin.

18

D. D

iscon

necto

r - This safety prevents the release

of the hamm

er unless the slide is fully forward

and/or the trigger is reset (released) between

rounds. This im

portant safety prevents seriousm

alfunctions from occurring, such as “slam

-fires” (rounds that fire during loading), autom

aticfire, or a round being fired out of the battery(w

ith the breech unlocked). The disconnector

disconnects the engagement of the trigger bar

and the sear actuator. The disconnector is

engaged (operating) after the slide has moved

2mm

to the rear. The slide presses the leading

edge of the disconnector down and into

engagement w

ith the trigger bar. When the

slide is fully forward, the leading edge of the

disengaged disconnector resides in a recessprovided in the bottom

of the slide.

SECTION III - OPERATION UNDER NORMAL CONDITIONS

WARNING

Always clear the pistol before handling it.

2.6 Clearin

g P

roced

ures

A. T

he Mark 23 pistol is not considered “clear” or

safe unless:1. T

he magazine is rem

oved,2. T

he slide is locked to the rear, and3. T

he chamber is free of brass or am

munition.

4. The safety lever is set on “safe”.

NE

VE

R A

SS

UM

E T

HE

PIS

TO

L IS

CL

EA

R!

B. T

o C

lear the P

istol:

1. Make su

re fing

ers are ou

tside o

f the trig

ger

gu

ard an

d th

e pisto

l is po

inted

in a safe

directio

n at all tim

es!2. D

ecock H

amm

er or E

ng

age S

afety - depressdecocking lever or engage the safety lever.

3. Rem

ove M

agazin

e - depress the magazine

release lever and remove the m

agazine fromthe fram

e.

19

4. Op

en S

lide

- lock slide open by pulling sliderearw

ard as you engage the slide release lever(up). W

atch for live round or empty case to be

ejected.5. In

spect C

ham

ber - inspect cham

ber for thepresence of a live round or em

pty case:a. V

isually view cham

ber through ejectionport.

b. Physically insert finger into cham

berthrough ejection port and check forpresence of cartridge case in cham

ber.c. R

emove any live rounds or em

pty casesfrom

the chamber or from

within the

weapon.

The pistol is now

considered “clear”.

2.7 Lo

adin

g an

d U

nlo

adin

g th

e Mag

azine - (S

eeF

igure 9)

The m

agazine of the Mark 23 pistol holds 10 rounds

of .45 caliber amm

unition in the comm

ercialm

agazine and 12 rounds in the Law E

nforcement/

Governm

ent magazine.

A. L

oad

ing

the M

agazin

e -1. H

old the magazine in one hand.

2. Hold a round betw

een the index finger andthum

b of the other hand with the projectile

pointing towards the palm

.3. P

ress the rim of the round dow

n against thefront edge of the follow

er or the top round inthe m

agazine and slide the round back underthe m

agazine lips.4. R

epeat steps 1 - 3 until the magazine is full.

The view

ing holes in the back of the magazine

allow the operator to confirm

the number of

rounds present within the m

agazine.

WA

RN

ING

Fo

rcefully in

serting

a load

ed m

agazin

e into

the M

ark 23 may cau

se the p

istol’s slid

e toclo

se, cham

berin

g a cartrid

ge an

d m

aking

the M

ark 23 ready to

fire.

Wh

en

ins

ertin

g a

ma

ga

zine

, alw

ay

s b

ec

erta

in th

at th

e p

isto

l is p

oin

ted

in a

sa

fed

irec

tion

with

yo

ur fin

ge

rs o

ff the

trigg

er

an

d o

uts

ide

the

trigg

er g

ua

rd. F

ailu

re to

do

so

co

uld

ca

us

e y

ou

to u

nin

ten

tion

ally

fire th

e p

isto

l, res

ultin

g in

se

riou

s in

jury

or d

ea

th.

20

Figure 9 Loading the M

agazine

B. U

nlo

adin

g th

e Mag

azine - exert pressure w

iththe finger on the base of the cartridge case andpush each round forw

ard out of the magazine

one round at a time until the m

agazine is empty.

2.8 Lo

adin

g P

roced

ure

A. A

dm

inistrative L

oad

ing

- used to initially loadthe pistol before it is to be fired.

Meth

od

A (S

lide rearw

ard, ch

amb

er emp

ty)

1. Make su

re fing

ers are ou

tside o

f trigg

erg

uard

and

pisto

l is po

inted

in a safe

directio

n at all tim

es!2. Insert m

agazine firmly into the fram

e. Tug on

magazine to insure that it is fully seated and

engaged.3. D

epress the slide release lever to release theslide and to cham

ber the first round.4. E

ngage safety lever or depress decockinglever.

5. Rem

ove magazine and top off w

ith oneadditional round.

6. Reinsert m

agazine insuring that it is fullyseated.

Meth

od

B (S

lide fo

rward

, cham

ber em

pty)

1. Make su

re fing

ers are ou

tside o

f trigg

erg

uard

and

pisto

l is po

inted

in a safe

directio

n at all tim

es!2. Insert m

agazine firmly into the fram

e. Tug on

magazine to insure that it is fully seated and

engaged.3. R

etract the slide fully and release. Do not ride

slide forward!

21

4. Engage safety lever or depress decocking

lever.5. R

emove m

agazine and top off with one

additional round.6. R

einsert magazine insuring that it is fully

seated.

B. T

actical Relo

adin

g - used to quickly reload

pistol once firing has begun.

Meth

od

A (S

lide rearw

ard, ch

amb

er emp

ty)

1. Make su

re fing

ers are ou

tside o

f trigg

erg

uard

and

pisto

l is po

inted

in a safe

directio

n at all tim

es!2. K

eep eyes on target area.3. D

epress the magazine release w

ith finger orthum

b of firing hand to drop magazine.

4. At the sam

e time, retrieve a full m

agazine with

the non-firing hand and insert firmly into the

frame. T

ug on magazine to insure that it is

fully seated and engaged.5. D

epress slide release to chamber first round.

6. Continue firing.

Meth

od

B (S

lide fo

rward

, rou

nd

s remain

ing

in m

agazin

e and

cham

ber)

1. Make su

re fing

ers are ou

tside o

f trigg

erg

uard

and

pisto

l is po

inted

in a safe

directio

n at all tim

es!2. K

eep eyes on target area.3. D

epress the magazine release w

ith finger orthum

b of firing hand to drop partially empty

magazine.

4. At the sam

e time, retrieve full m

agazine with

non-firing hand and insert firmly into the fram

e.T

ug on the magazine to insure that it is fully

seated and engaged.5. W

eapon is now back at full capacity w

ithoutrendering cham

ber empty and w

eaponuseless.

6. Continue firing

2.9 Read

ying

the P

istol fo

r Firin

g

Disengage the safety lever (if engaged). R

ed hazarddot w

ill be visible above safety lever.

22

WARNING

1. BE SURE OF YOUR TARGET AND WHAT’S

BEHIND IT! Even a .45 caliber projectile can

easily penetrate wood, plasterboard walls, or

a car door, and can travel as far as one mile!

2. Ensure that all parts of your hand and body

are kept away from the muzzle of the pistol

at

all times!3. Always wear eye and ear protection where

possible when firing the pistol.

4. Whenever the pistol is dropped on a hard

surface landing on the hammer (cocked or

down), it should be sent to the HK Service

Department as soon as practicable to inspect

the sear axle. If the sear axle is bent, it shouldbe replaced.

2.10 Firin

g th

e Pisto

l

A. S

ing

le-action

mo

de (H

amm

er back/cocked)A

ffords operator the best and lightest trigger pull(≈ 4.8 lbs.) for precise and accurate bulletplacem

ent.W

ith manual safety disengaged:

1. Aim

at the target.2. F

ire the weapon by pressing the trigger straight

to the rear with gradually increasing pressure.

3. Engage the safety lever to rem

ain in the single-action m

ode once firing is completed.

CA

UTIO

NSingle action mode trigger pull is lighter &

shorter than double action mode. Keep your

finger off the trigger & outside the trigger

guard except when firing the

Mark 23.

B. D

ou

ble-actio

n m

od

e (Ham

mer dow

n/uncocked)P

rovides the operator with a long, heavy (≈12.1

lbs.) trigger pull for the first shot only. Subsequent

shots will be fired in single-action m

ode as theslide w

ill automatically cock the ham

mer after

each round is fired. The double-action m

ode offire is often the preferred m

ode of fire when

safety during handling and carrying is of greaterconcern than first round accuracy.1. A

im at the target.

2. Fire the w

eapon by pressing the trigger straightto the rear w

ith gradually increasing pressure.3. D

epress the decocking lever to lower the

hamm

er to return to the double-action mode

once firing is complete, or engage the safety

lever to remain in the single action m

ode.

23

SECTION IV - OPERATION UNDER UNUSUAL CONDITIONS

NOTE

Unusual conditions are defined as any climatic

condition requiring special maintenance of

the pistol. Perform the maintenance outlined

for the climate that most applies to your

operational area. Refer to paragraph 3.9 for

lubrication instructions.

CAUTION

If extensive corrosion is found and cleaning

does not solve the problem, contact t

he HK

Service Department.

2.11 Extrem

e Co

ld

A. W

hen operating pistol in extremely cold

climates, clean and lubricate the pistol inside at

room tem

perature if possible.B

. Apply a light coat of LA

W (Lubricant, A

rcticW

eapons) to all functional parts.C

. To prevent freezing, keep the pistol covered

when m

oving from a w

arm to a cold area. T

his

will allow

gradual cooling.D

. Alw

ays keep the pistol dry.E

. Do not lay a hot pistol in snow

or ice.F

. Keep am

munition dry; m

oisture will cause

malfunctions. D

o not lubricate theam

munition.

G. A

lways keep snow

out of the bore of the barrel.If snow

should get into the bore, clean the borebefore firing using a sw

ab and cleaning rod.

2.12 Ho

t, Wet C

limates

A. P

erform m

aintenance more frequently. Inspect

hidden surfaces for corrosion. If corrosion isfound, clean and lubricate.

B. T

o help prevent corrosion, remove hand prints

with a cloth. D

ry and lubricate the pistol with

CLP

/LSA

(Cleaner, Lubricant, P

rotectant).C

. Check am

munition and m

agazines frequently forcorrosion. C

lean the magazine using C

LP/LS

Aand w

ipe dry with a cloth. If necessary, clean

amm

unition with a dry cloth.

D. A

lways keep m

ud out of the barrel. If mud

should get into the bore, clean it before firingusing a sw

ab and cleaning rod.

24

2.13 Ho

t, Dry C

limates

A. D

ust and sand will get into pistol and cause

malfunctions and excessive w

ear on component

contact surfaces during firing. Keep the pistol

covered when possible.

B. C

orrosion is less likely to form on m

etal parts ina dry clim

ate. Therefore, lightly lubricate

internal working surfaces only w

ith CLP

/LSA

.D

o not lubricate external parts of the pistol.W

ipe any excess lubricant from exposed

surfaces. Do not lubricate internal com

ponentsof m

agazine.

2.14 Heavy R

ain an

d W

ater Op

eration

s - All

Clim

ates

A. P

erform m

aintenance in accordance with the

appropriate climatic conditions.

B. A

lways attem

pt to keep pistol dry.C

. Alw

ays try to drain any water from

barrel prior tofiring. D

ry the bore with a sw

ab and cleaningrod.

D. Lightly lube the bore and cham

ber. Generously

lube internal and external surfaces of the pistol

with C

LP/LS

A.

E. In extrem

e or prolonged wet or saltw

aterconditions, cover serial num

ber and proof mark

on barrel and slide with a tem

porary protectivecoating. T

hese are etched on through theperm

anent protective coating on the barrel andslide and therefore m

ay corrode under theseconditions.

25

SE

CT

ION

V - M

AL

FU

NC

TIO

NS

AN

D S

TO

PP

AG

ES

2.15 Rem

edial A

ction

- Rem

edial Action is the

action performed to rem

edy an unanticipatedinterruption of the pistol’s operation and place thepistol back into operation.

WARNING

During remedial action, make certain the pis-

tol is pointed in a safe direction at all times.

A. C

lear the p

istol!

B. A

ttempt to lock slide.

C. R

emove m

agazine.D

. Inspect chamber.

E. Insert fresh m

agazineF

. Release slide.

G. A

ttempt to fire the pistol.

If the Mark 23 fails to fire, return the w

eapon to theH

K S

ervice Departm

ent for service.

WARNING

If a round is assembled without powder (a

fault of the manufacturing process), the primer

alone has enough power to propel the

projectile into the bore. A projectile lodged inthe bore may cause damage to the barrel and/

or the pistol if another round is fired and

could cause personal injury. This event is

commonly called a “pop and no kick” or

“squib load” and is characterized by a much

reduced report and little or no movement of

the slide. An alert operator should notice the

occurrence of this event in time to avoid

firing the next round.

Selectio

n an

d U

se of a H

olster -

Selectio

n - W

hen selecting a carrying holster for theH

K M

ark 23, it is important to consider the follow

ingpoints:

1. The holster m

ust not make contact w

ith or actuateany of the operating controls. T

his includes theham

mer, slide release, m

agazine release lever,and m

ost importantly the safety lever and the

26

trigger. The design of the holster m

ust also notactuate these controls w

hen the pistol is carried in,draw

n from, or returned to the holster.

2. The holster should not cause the slide to m

ove(unlock) w

hen the pistol is returned to the holster.3. A

ccomm

odations must be provided in the holster

for any accessories that might be present on the

pistol.4. C

hoose a holster designed for the Mark 23.

Retu

rnin

g th

e Pisto

l to th

e Ho

lster - The H

KM

ark 23 must be m

ade “safe” (or cleared) prior toreturning it to the holster. T

he pistol is considered safeto return it to the holster w

hen:

1. All fingers are off of the trigger and out of the trigger

guard and;2. T

he pistol is “clear” or;3. T

he hamm

er is in the decocked (down) position or;

4. The safety lever is engaged in the safe position

when the ham

mer is cocked.

WARNING

The pistol must never be returned to the

holster unless the above procedures have

been followed or injury or death could occur.

27

CHAPTER 3 MAINTENANCE INSTRUCTIONS

SECTION I - TOOLS & EQUIPMENT

NOTE

The service life and performance of your HK

Mark 23 is dependent upon the correct

handling and proper care by the operator.

3.1 Op

erator T

oo

ls and

Eq

uip

men

t Req

uired

. At

a minim

um, you w

ill require the following m

aterialsto m

aintain the Mark 23 pistol and its com

ponents:

• Cleaning rod w

ith handle and eyelet• Long handled nylon brush• B

ronze bristle bore brush (.45 caliber)• C

otton swabs

• Solvent/bore cleaner/C

LP• C

leaning patches (.45 caliber)• R

ag

CAUTION

Use safety goggles when using solvents and

exercise care if using compressed air.

SECTION II - PREVENTATIVE MAINTENANCE (PM)

SERVICE CHECKS & MAINTENANCE PROCEDURES

3.2 Gen

eral - This P

M S

ervice section lists thoserequired checks and services to be perform

ed bypersonnel w

ho operate the Mark 23 pistol. T

hissection includes the services required to prepare thepistol for operation, to check the pistol duringoperation, and to ensure proper function afterm

aintenance. Before perform

ing any PM

Service

procedures, ensure that the Firearm

Service R

ecordhas been updated w

ith the correct round count andany P

M S

ervice procedures documented. If your

equipment fails to operate, refer to the T

rouble-shooting T

able in Section III.

WARNING

Before starting an inspection procedure

CLEAR THE PISTOL! I

nspect the chamber to

ensure that it is empty. Do not keep live

ammunition near maintenance /work areas.

28

Figure 10

Rem

oving or Installing the Slide R

elease

CAUTION

Hold the recoil/buffer spring assembly in place

while removing the slide from the frame.

NOTE

Before starting any PM Service procedure

ensure that the Firearm Service Record has

been updated with the correct round count

and any PM Service performed documented.

3.3 Disassem

bly (F

ield stripping)

A. P

istol

1. Clear th

e pisto

l!2. D

epress slide release and allow slide to m

oveforw

ard.3. If applicable, rem

ove any mounted accesso-

ries.4. U

sing the left hand, retract and hold the slideto the rear approxim

ately 22 mm

until the frontend of the slide release is centered on therecess visible on the left side of the slide (S

eeF

igure 10).5. W

ith he right hand push the slide release intothe recess on the right side of the fram

e, liftand com

pletely remove the slide release from

the left side of the frame.

Recess

Slide

Release

29

10-Ro

un

d C

ivilian M

agazin

e

1. Using a blunt pointed instrum

ent depress thelocking insert detente located in the floor platean

d h

old

it there.

2. Place a portion of either hand over the base of

the magazine to control the release of the

magazine spring and locking insert.

3. With the locking detente still depressed,

squeeze the floor plate locking tabs located onthe right and left sides of the m

agazine.4. G

radu

ally allow the locking insert and m

agazinespring to expand out of the m

agazine housing.5. R

emove the locking insert, m

agazine spring andm

agazine follower from

the magazine housing.

CAUTION

Beware of the spring tension exerted by the

magazine spring while removing and

installing the magazine floor plate. Keep the

base of the magazine pointed in a safe

direction (away from face and eyes) during

disassembly and assembly.

6. Rem

ove the slide with barrel and captured

recoil/buffer spring assembly off of the fram

e bysliding it forw

ard.7. R

emove the captured recoil/buffer spring

assembly from

the barrel and slide by lifting upon the rear of the guide rod. T

he entireassem

bly can now be lifted out of the slide.

8. Lift the rear of the barrel by the locking blockand w

ithdraw it from

the slide.

B. M

agazin

e

12-Ro

un

d L

aw E

nfo

rcemen

t Mag

azine

1. Using a blunt pointed instrum

ent depress thelocking detent protruding through the bottom

ofthe m

agazine floor plate and ho

ld it th

ere.2. P

lace a portion of either hand over the base ofthe m

agazine to control the release of them

agazine spring and locking plate.3. S

low

ly slide the floor plate forward off of the

magazine housing.

4. Gradually allow

the locking plate and magazine

spring to expand out of the magazine housing.

5. Rem

ove the locking plate, magazine spring and

magazine follow

er from the m

agazine housing.

30

CAUTION

Operator disassembly of the Mark 23 pistol is

now complete. Only trained HK Service

Department personnel may disassemble the

weapon further.

3.4 Reassem

bly (F

rom field strip)

A. M

agazin

e

12-Ro

un

d L

aw E

nfo

rcemen

t Mag

azine

1. Place the m

agazine follower onto the end of the

magazine spring having the loop at the end of

the wire on the left side of the follow

er.2. Insert the follow

er and the magazine spring into

the magazine housing.

3. Place the locking plate onto the protruding end

of the magazine spring so that the locking

detent is visible (see Figure 11A

).4. P

ush the locking plate down into the m

agazinehousing against the pressure of the m

agazinespring and h

old

it there.

5. Slide the floor plate over the base of the

magazine housing and locking plate from

frontto rear m

aking sure that:a. T

he floor plate engages the tabs located on

the left and right sides of the magazine

housing.b. T

he floor plate is fully seated on the magazine

housing.c. T

he locking detent fits within the hole provided

in the floor plate.d. C

heck the magazine for proper assem

bly byinsuring that the follow

er slides up and down

freely within the m

agazine housing and with

spring tension. Also check that the m

agazinefollow

er rises within the housing to be nearly

flush against the bottom of the m

agazine lips.

Figure 11A

Assem

bly of Magazine F

ollower &

Spring

(12-Round Law

Enforcem

ent Magazine)

magazine housing

floor plate

magazine

follower

locking plate

magazine spring

31

Figure 11B

10-Round C

ivilian Magazine

(Disassem

bled)

10-Ro

un

d C

ivilian M

agazin

e (see Figure 11B

)

1. Place the m

agazine follower onto the

magazine spring w

ith the end of the springpositioned on the left of the follow

er.2. Insert the follow

er and magazine spring into

the magazine housing.

3. Place the locking insert (on 10-round

magazines) onto the protruding end of the

magazine spring so that the rounded corners

face towards the front of the m

agazine.

4. Push the locking plate dow

n into the magazine

housing against the pressure of the magazine

spring and

ho

ld it th

ere.5. P

ush the floor plate up onto the base of them

agazine housing until the locking tabsengage in the sides of the housing. C

heck tosee if the locking tabs on the floor plate aresecurely locked into the housing and thelocking detente on the locking plate fits w

ithinthe hole in the floor plate.

6. Check the m

agazine for proper assembly by

insuring that the follower slides up and dow

nfreely w

ithin the magazine housing and w

ithspring tension. A

lso check that the magazine

follower rises w

ithin the magazine housing to

be nearly flush against the bottom of the

magazine lips.

B. P

istol

1. Insert the muzzle of the barrel through the

large hole located in the front of the slide.2. D

rop the barrel down into the slide and push it

forward until the O

-ring engages the slide, thelocking block fits w

ithin the ejection port, andthe angled locking surface of the locking blockare visible along the bottom

of the slide. The

magazine housing

floor plate

magazine

follower

locking insert

magazine spring

32

O-ring w

ill now hold the m

uzzle tight in thefront of the slide.

3. Install the captured recoil/buffer springassem

bly into the slide so that the front of therecoil spring guide rod engages in the sm

allerhole located in the front of the slide.

4. Align the opposing angled locking surfaces of

the recoil spring guide rod with those located

on the bottom of the barrel locking block.

5. Push the rear of the recoil/buffer spring

assembly forw

ard enough so that the recoilspring retainer can be engaged on the shelfprovided on the front of the barrel lockingblock (see F

igure 12).6. H

old the slide in the right hand with the thum

bholding the rear end of the recoil/buffer springassem

bly in place on the slide (see Figure 13).

7. Hold the fram

e in the left hand. Position the

rear of the slide above the front edge of thefram

e.8. D

raw the slide back onto the fram

e so that therails of the locking insert and guiding part slidew

ithin the grooves in the slide.9. R

etract the slide to the point where the recess

in the left side of the slide is centered on thehole w

here the axle of the slide release will go.

10. Hold the slide in this position and insert the

slide release from the left to right into the

frame until it is flush w

ith the side of the frame

and locks in place.

Figure 12 P

roper Position for the C

aptured Recoil/

Buffer S

pring Assem

bly on the Barrel Locking B

lock

locking blockbarrel

threadsO

-ring

shelfbuffer spring

recoil springguide rod

recoil spring C

-cliprecoil spring

retainer

33

Figure 13 C

orrect Position for H

olding Slide

for Reassem

bly

NOTE

Operator reassembly of the Mark 23 pistol is

now complete, but not finished without a

safety/function check.

3.5 Safety/F

un

ction

Ch

eck

A. A

safety/function check should be performed

anytime the pistol is reassem

bled. This quick

check indicates whether or not the pistol w

asproperly assem

bled and with all the com

po-nents. A

properly executed safety/functioncheck can also reveal m

any of the more obvious

malfunctions that could occur betw

een theinteractive com

ponents of the pistol.

B. A

lways clear the pistol before perform

ing asafety/function check! D

on

’t assum

e the

pisto

l is clear!1. C

lear the p

istol!

2. Actuate the slide and the operating controls to

insure that:a. M

agazin

e and

catch - the m

agazine isheld securely in place by the m

agazinecatch and that it drops free of the fram

ew

hen the catch is depressed.b. S

lide - the slide m

oves freely and without

binding on the frame (w

ith and without a

magazine installed).

c. Barrel - the barrel locking block does lock

fully into battery within the ejection port of

the slide as the slide is closed.d. S

lide R

elease -1) T

he slide release does hold the slideopen w

hen retracted while:

frame

slide

thumb holding recoil/buffer spring

assembly on the locking block

34

a) an empty m

agazine is in place.b) the slide release is engaged (pressed

upwards).

2) The slide release does perm

it the slide tosnap forw

ard when:

a) the slide release is depressed.b) the slide is retracted w

ithout am

agazine installed.3) T

he slide release does rebound with

spring pressure.

3. Perform

the following safety checks:

a. Safety L

ever Test.

1) With the pistol unloaded and ham

mer

down (uncocked) attem

pt to press thesafety lever upw

ard into the safe position.T

he safety lever should not engage. If thesafety lever engages, return the pistol tothe H

K S

ervice Departm

ent for service.

2) With the pistol unloaded, the ham

mer

cocked, move the safety lever several

times from

the “safe” to “fire” position. Ifthe safety lever does not have a pro-

nounced stop when m

oved from “safe” to

“fire” position and back, return the pistolto the H

K S

ervice Departm

ent for service.

3) With the pistol unloaded, cock the

hamm

er and press the safety leverupw

ard into the safe position. Grasp the

pistol in the shooting position andsqueeze the trigger three or four tim

es. Ifthe ham

mer falls, return the pistol to the

HK

Service D

epartment for service.

b. D

ecockin

g L

ever Test.

1) With the pistol unloaded, cock the ham

mer

and depress the decocking lever. If theham

mer does not fall or the decocking lever

does not rebound (upward into its norm

alposition) w

ith spring pressure, return thepistol to the H

K S

ervice Departm

ent forservice.

2) With the pistol unloaded, cock the

hamm

er and press the safety leverupw

ard into the safe position. Attem

pt todepress the decocking lever three or four

35

times. If the ham

mer falls, return the

pistol to the HK

Service D

epartment for

service.

c. Deco

cked (h

amm

er do

wn

) Test.

NOTE

On the Mark 23 pistol when decocked (hammer

down), the sear is engaged with the hammer at

a rebounded stop position not touching the

rear of the firing pin.

1) With the pistol unloaded, squeeze the

trigger allowing the ham

mer to cycle in the

double action mode. A

fter the hamm

erdrops, retain pressure on the trigger. W

iththe non-firing hand apply pressure w

ith yourfinger tips on the rear of the ham

mer. T

heham

mer should m

ove forward tow

ard thefiring pin. R

elease pressure on the triggerw

hile still retaining pressure with fingers on

hamm

er. Release pressure on ham

mer. If

the hamm

er fails to spring back into the stopposition, return the pistol to the H

K S

erviceD

epartment for service.

2) With the pistol unloaded, ham

mer

uncocked, trigger forward, apply pressure

to the hamm

er with your finger tips. If the

hamm

er moves forw

ard to the firing pin,return the pistol to the H

K S

erviceD

epartment for service.

d. D

iscon

necto

r and

Trig

ger T

est.

1) With the pistol unloaded, cock the

hamm

er, push the slide rearward

approximately 3/16 inches (2m

m) and

hold in that position while squeezing the

trigger. If the hamm

er falls, return thepistol to the H

K S

ervice Departm

ent forservice.

2) With the pistol unloaded, pull the slide

rearward until the slide stop w

ill engage.S

queeze the trigger and release the slideforw

ard simultaneously. If the ham

mer

falls, return the pistol to the HK

Service

Departm

ent for service.

36

3) With the pistol unloaded, pull the slide

rearward and engage the slide. S

queezethe trigger and release the slide forw

ardsim

ultaneously. Release pressure on the

trigger. If the trigger does not return to itsnorm

al position, return the pistol to theH

K S

ervice Departm

ent for service.S

queeze the trigger and the hamm

ershould fall. If the ham

mer does not fall,

return the pistol to the HK

Service

Departm

ent for service.

4) With the pistol unloaded and the trigger

forward, apply thum

b pressure to thecocked ham

mer. If the ham

mer low

erssolely as a result of thum

b pressure,return the pistol to the H

K S

erviceD

epartment for service.

3.6 Fu

nctio

n F

iring

If any corrective action was accom

plished, the pistolshall be function fired a full m

agazine prior to beingcleaned and returned to service use.

3.7 Clean

ing

- perfo

rmed

after each firin

g, o

revery tw

elve (12) mo

nth

s, or after an

y expo

sure

to extrem

e enviro

nm

ental co

nd

ition

s such

assalt, fo

g, san

d, d

ust, m

ud

, water, etc.

A. N

orm

al Clean

ing

-1. C

lear the p

istol!

2. Disassem

ble the pistol into the major assem

-bly groups.a. S

lide -

1) Scrub all internal surfaces of the slide

using the nylon brush moistened w

ithsolvent.

2) Rem

ove all loose fouling from all surfaces

of the slide using a rag and cotton swabs.

b. Reco

il/bu

ffer sprin

g assem

bly - rem

oveall visible fouling using solvent, a nylonbrush, a rag, and cotton sw

abs.c. B

arrel with

lockin

g b

lock -

1) Moisten the bronze bore brush w

ithsolvent and scrub the bore from

chamber

to muzzle at least six passes, back and

forth. (Note: R

epeat steps 1 and 2 until acleaning patch can be pushed through thebore and rem

ains clean.)

37

NO

TE

All p

arts of th

e HK

Mark 23 can

be im

mersed

inan

y cleanin

g so

lvent th

at it is safe to p

ut yo

ur

han

ds in

to. G

asolin

e and

oth

er mo

tor fu

els aren

ot au

tho

rized clean

ing

solven

ts. Avo

id clean

-in

g th

e frame in

an u

ltrason

ic cleaner as th

is canrem

ove th

e colo

red “safe” an

d “fire” d

ots.

3.8 Insp

ection

During and after cleaning the operator should

inspect the pistol and its components for any

irregularities that may cause problem

s during itsoperation. If any potential deficiencies are noted,they should be corrected im

mediately and/or

brought to the attention of the HK

Service D

epart-m

ent for service.

A. V

isually In

spect th

e Pisto

l and

Mag

azine fo

r:

1. Dam

aged or missing parts

2. Improper assem

bly or function3. A

bsence of free movem

ent, where applicable

4. Absence of spring tension, w

here applicable

2) Rem

ove the loose fouling using cleaningpatches.

3) Scrub outside surfaces of barrel and

locking block with the nylon brush

moistened w

ith solvent.4) S

crub the threads of the barrel and O-ring

with the nylon brush m

oistened with

solvent.5) R

emove all loose fouling using a rag and

cotton swabs.

d. Fram

e -1) S

crub all internal surfaces where carbon

fouling is visible using the nylon brushm

oistened with solvent. C

oncentrate onthe area norm

ally covered by the slide.2) U

sing the rag and cotton swabs, rem

ove allloose fouling from

all areas of the frame.

e. Mag

azine -

1) The m

agazine is disassembled for

cleaning.2) S

crub the top of the magazine, concen-

trating on the follower and feed lips, using

the nylon brush moistened w

ith solvent.3) U

sing the rag and cotton swabs, rem

oveall loose fouling from

all surfaces of them

agazine.

38

5. Unaccustom

ed looseness6. P

arts exhibiting signs of cracks, burrs, dents,or obvious signs of dam

age or stress7. P

resence of stops or tactile clicks in controls,w

here applicable8. G

eneral overall cleanliness9. P

resence of proper lubrication10. P

resence of corrosion or degradation of surface finish11. R

ubber hamm

er spur for cracks or chips

CAUTION

If the rubber hammer spur is badly cracked or

chipped, drop safety could be degraded. Pistol

should be returned to HK Service Department

to replace hammer.

3.9 Lu

bricatio

n

All m

etal surfaces of the Mark 23 pistol have a

special surface treatment that resists all types of

corrosion including corrosion resulting fromexposure to salt w

ater. How

ever, this surfacetreatm

ent does not reduce friction between parts,

therefore, lubricant must be applied to the pistol.

Any type of high-quality, m

edium w

eight lubricant(oil or grease) specifically designed for use onfirearm

s, such as “Break-F

ree” (C.L.P

.), will w

orkw

ell on the Mark 23 pistol.

Do not use lubricants that boast of their ability to

penetrate metal as these substances m

ay deadenprim

ers.

A. W

here and

ho

w m

uch

?

No

Lu

be - (surface is dry and not slippery to the

touch)• P

lastic components

Lig

ht L

ub

e - (finger run across surface yieldslittle or no lube)• B

ore, chamber, and exterior of barrel

• All m

etal parts• A

ll internal parts in slide and frame

• Magazine housing and spring

• Recoil/buffer spring assem

bly• S

ights• O

-ring

39

Med

ium

Lu

be - (finger run across surface

yields some lube but lube does not run dow

nsurface w

hen held in a vertical position)• B

arrel locking block• S

lide rails• A

ll operating controls• Locking insert and guiding part• E

xtractor

Heavy L

ub

e - (Lube runs down surface w

henheld in a vertical position)

NOTE

No heavy lube is required on the Mark 23

pistol.

Reapply lubrication periodically during firing as it

burns off from the heat. A

pply lubricant using ashaving brush, cotton sw

abs, patches, or rag. Aspray bottle also w

orks well using com

pressed air tocirculate the lubricant into all parts and to rem

ovethe excess.

40

NOTE

All windage and elevation adjustments are

made using only the rear sight.

1. Win

dag

e adju

stmen

ts - to adjust thehorizontal (left and right) im

pact of theprojectile follow

these steps below:

a. Clear th

e Pisto

l!b. N

ote the index mark on the rear sight and

its relationship to the index mark on the

slide.c. Loosen the rear sight retaining screw

usinga screw

driver.d. W

ith a small ham

mer and brass or soft

metal drift punch, drift the sight to the:

1) LEF

T to m

ove the point of impact to the

left.2) R

IGH

T to m

ove the point of impact to the

right.3) T

he amount of m

ovement w

ill depend onthe individual shooter and the am

munition

used.

SE

CT

ION

III - AD

JUS

TM

EN

T O

F S

IGH

TS

Descrip

tion

-1. T

he mechanical sights supplied w

ith the Mark

23 pistol are comprised of a fixed front sight

post combined w

ith a rear sight with u-shaped

notch of a conventional configuration. Both

front and rear sights are held in place on theslide w

ithin a standard dovetail groove. The

rear sight is also secured with a retaining

screw and is adjustable for w

indage andelevation.

2. Both front and rear sights contain w

hite circles(or cylindrical tritium

capsules) that appear asdots to the operator. O

ne dot is positioned oneither side of the rear sight aperture and in thecenter of the front sight post. W

hen the sightsare properly aligned vertically and horizontally,so are these dots. T

hus, the three dots can beused for rapid acquisition of the sights andproper sight alignm

ent.

Ad

justm

ent - the battle sight zero of the M

ark 23pistol is easily adjusted by m

oving or replacingthe rear sight.

41

NOTE

Always strike the sight on the sight base, not

on the sight blades.

e. Retighten the rear sight retaining screw

.f. C

onfirm your battlesight zero by firing the

pistol again.

2. Elevatio

n A

dju

stmen

ts -To adjust the vertical

(up and down) im

pact of the projectile followthese steps below

:

a. Clear th

e pisto

l!b. D

etermine the am

ount of vertical change, ininches, that is required at 25 m

eters. Note

the index mark on the rear sight and its

relationship to the index mark on the slide.

c. Loosen and remove the rear sight retaining

screw using a screw

driver.d. W

ith a small ham

mer and brass or soft

metal drift punch, drift the sight com

pletelyout of either side of the dovetail groove.

e. Note the m

arking on the bottom of the rear

sight. (The standard sight is unm

arked),f. S

elect a higher or lower rear sight from

Figure 14.

g. Using the brass or soft m

etal punch andham

mer, install the new

sight into thedovetail groove.

h. Align the index m

arks of the rear sight andslide as noted in step b above.

i. Reinstall and tighten the rear sight retaining

screw.

j. Confirm

your battle sight zero by firing thepistol again.

3. Rear S

igh

t Selectio

n - T

he rear sight ism

arked with -6, -4, -2, unm

arked, +2, +

4, or +6.

This m

arking represents the amount of vertical

change, in inches, that occurs when that sight is

exchanged with the sight originally installed in

the pistol.

1) To R

AIS

E the point of im

pact, install ahigher rear sight.

2) To LO

WE

R the point of im

pact, install alow

er sight.

Exam

ple: T

he pistol is shooting 4 inches high at25 m

eters. We w

ant the pistol to shoot dead-on(point of aim

, point of impact). T

he rear sight

42

removed from

the pistol is unmarked (standard).

1) Figure 25 show

s that the rear sight marked -4

would low

er the point of impact tw

o increments,

or a total of 4 inches, from the standard

unmarked rear sight rem

oved from the pistol.

2) The -4 sight w

ould be the correct one toinstall. O

btain the exchangeable rearsight from

the kit delivered with the

pistols.

Raise Point of Impact (Inches)

Lower Point of Impact (Inches)

-6

+6

+4

-4

-2

No M

arking (Standard)

+2

Figure 14

C. Z

eroin

g1. T

he battlesight zero of the Mark 23 pistol is set

by the manufacturer using +

P 185 grain JH

Pam

munition. T

he pistol is fired from a m

achinerest at a target positioned 25 m

eters from the

pistol. The pistol is zeroed point of aim

, pointof im

pact (PO

A/P

OI). T

his means the im

pactof the projectile on target w

ill coincide with the

point of aim of the sights at 25 m

eters.

2. Each individual operator of the M

ark 23 pistolcan battlesight zero their pistol to their uniqueshooting style by adjusting the sights inaccordance w

ith the procedures in subpara-graphs 1 - 3 above.

43

SE

CT

ION

IV - T

RO

UB

LE

SH

OO

TIN

G P

RO

CE

DU

RE

S

3.11 Op

erator T

rou

blesh

oo

ting

Pro

cedu

res

PR

OB

LEM

SY

MP

TO

M/C

AU

SE

RE

ME

DY

1. Round does not feed

Fouled m

agazine or pistolC

lean and lube pistol and magazine

Improperly assem

bledA

ssemble correctly

Incorrect loading procedure usedLoad pistol in accordance w

ith instructionsin operator’s m

anual

Unserviceable m

agazineR

eplace magazine

2. Round does not cham

berD

irty or damaged m

agazineC

lean and lube or replace magazine

Obstruction present in cham

berR

emove obstruction, clean and lube

and/or borecham

ber/bore

Bent or dam

aged recoil spring,R

eturn pistol to the HK

Service D

epart-buffer spring, or guide rod. B

ufferm

ent for servicespring retainer roll pin drift. *

* NOTE

Always inspect the buffer spring retainer roll pin for drift. If not firmly seated and centered in the guide

rod, return to the HK Service Department for replacement.

44

PR

OB

LEM

SY

MP

TO

M/C

AU

SE

RE

ME

DY

3. Slide does not lock

Fouled barrel locking block or slide

Clean and lube barrel locking block and

fully forward

slide

Dry com

ponent parts or pistolLubricate pistol in accordance w

ithinstructions in operator’s m

anual

Dam

aged or burred slide, barrelR

eturn pistol to the HK

Service D

epart-locking block, or recoil/buffer

ment for service

spring assembly. B

uffer springretainer roll pin drift. *

4. Pistol does not fire

Faulty am

munition

Replace am

munition

Little or no sign of firing pin strikeR

eturn pistol to the HK

Service D

epart-(indent) on prim

erm

ent for service

5. Slide does not unlock

Faulty am

munition, determ

ined byC

heck bore for obstruction and replaceshort recoil

amm

unition

Check for broken or dam

aged slide,R

eturn pistol to the HK

Service D

epart-barrel locking block or recoil/buffer

ment for service

spring assembly. B

uffer springretainer roll pin drift. *

45

PR

OB

LEM

SY

MP

TO

M/C

AU

SE

RE

ME

DY

6. Cartridge does not extract

Fouled cham

berC

lean and lube

Ruptured cartridge case in cham

berR

emove ruptured case, clean and lube

chamber

Fouled or corroded am

munition

Replace am

munition

Pitted or dam

aged chamber

Return pistol to the H

K S

ervice Depart-

ment for service

Broken or dam

aged extractorR

eturn pistol to the HK

Service D

epart-or extractor spring

ment for service

7. Operating controls do not

Dam

aged or improperly assem

bledR

eturn pistol to the HK

Service D

epart-function as described

component parts

ment for service

in operator’s manual

8. Accuracy degradation

Dam

aged or missing O

-ringR

eplace O-ring

46

Position N

o. Item

Description

Part N

o.

1extractor

2157072

extractor spring215708

3rear sight retaining screw

2157114

rear sight, 6.3mm

standard (unmarked)

215770rear sight, 5.5m

m (-4)*

215767rear sight, 5.9m

m (-2)*

215768rear sight, 6.7m

m (+

2)*215771

rear sight, 7.1mm

(+4)*

215774rear sight, 7.5m

m (+

6)*215783

5front sight

2157216

firing pin215705

7firing pin spring

2157068

firing pin block215709

9firing pin block spring

21571010

firing pin retaining pin986432

11extractor pin

98643212

slide215667

13barrel

21567114

O-ring

98642915

recoil spring guide rod215724

16recoil spring retainer

21572517

buffer spring215726

18dual roll pin (buffer spring retainer)

98643319

buffer spring retainer215727

20spring ring

92919121

washer

21572822

recoil spring215729

23trigger bar, com

plete215760

24trigger bar spring

21573425

c-clip (decocker)927062

26decocking spring

21474327

decocker215742

28roll pin (ejector)

98643129

ejector215752

30sear

21574831

sear spring215749

32sear actuator

21575033

disconnector215751

34sear axle

215753

35roll pin (right safety lever)

98643036

right safety lever215744

37sear block

21575438

decocking lockout215745

39ham

mer axle

21573840

hamm

er, complete

21577241

hamm

er rebound spring215739

42ham

mer strut

21574043

hamm

er strut spring215741

44insert

21573145

locking bolt215732

46fram

e215976

47safety detent

21574648

safety detent spring215747

49left safety lever

21576950

decocking lever215766

51m

agazine release pin986432

52m

agazine release spring215737

53m

agazine release215775

54slide release spring

21573355

trigger215735

56trigger pin

21573657

slide release lever, complete

21576358

magazine housing (12-rd m

agazine)215778

58Am

agazine housing (10-rd magazine)*

21567259

follower (10 &

12-rd magazine)

21577960

locking plate (12-rd magazine)

21578160A

locking plate (10-rd magazine)*

21485361

floor plate (12-rd magazine)

21578061A

floor plate (10-rd magazine)*

21567362

magazine spring (12-rd m

agazine)215782

62Am

agazine spring (10-rd magazine)*

21482163

locking insert (molded into fram

e)64

trigger guard insert (molded into fram

e)65

guiding part (molded into fram

e)m

agazine (12-rd with LE

markings), com

plete*215668

magazine (10-rd), com

plete*215670

*not pictured

Position N

o. Item

Description

Part N

o.

3.12 Parts Listing for M

ark 23 Pistol

47

Figure 15 E

xploded Diagram

HK Mark 23 Pistol

35

42

1

67

8

9

1110

19

18

1716

15

14

13 12

20

2122

2324

2526

27

32

28

35 34

33

313029

40

36

37

38

39

4847

46

454443

42

41

49

50

51

52

53

6354

55

56

57

58

59

62

60

61

6465

48

CHAPTER 4- AMMUNITION

The M

ark 23 pistol was designed to operate best

using two types of .45 A

CP

caliber amm

unition.T

hey are:

A. M

1911 230 grain Ball

B. C

omm

ercially Manufactured 185 grain +

PJacketed H

ollow P

oint (JHP

)

WA

RN

ING

Th

e use o

f inco

rrect amm

un

ition

in th

e pisto

lco

uld

result in

dam

age to

the p

istol an

d/o

rin

jury to

the o

perato

r or b

ystand

ers

DO

NO

T U

SE

• Reloaded, rem

anufactured, or military surplus

(foreign or outdated) amm

unition• A

mm

unition loaded in aluminum

cartridge cases• C

racked, split, dirty or corroded cases• A

mm

unition assembled w

ith corrosive primer

and/or propellent• A

mm

unition assembled w

ith projectile damaged

or pushed into cartridge case past crimp

• Am

munition exposed to oil, grease, w

ater, ordirect sunlight. R

emove contam

inants if

possible before use and cool down am

munition

exposed to direct sunlight or heat. (Exposure to

sources of heat could raise the chamber

pressure of the cartridge above safe limits).

WA

RN

ING

Heckler &

Ko

ch sp

ecifically disclaim

s any re-

spo

nsib

ilities for an

y dam

age o

r inju

ry that

sho

uld

occu

r becau

se of, o

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