Ballistics and Explosives

PWISTA ForensicsDress code Policy

http://video.google.com/videoplay?docid=277245771309014482&q=guns&hl=en

Ballistics

“The science of the motion of projectiles, such as bullets from a gun. It is divided into three branches: interior ballistics, exterior ballistics, and terminal ballistics. Interior ballistics studies the projectile in the gun while exterior ballistics studies the projectile in and through the air. Finally terminal ballistics is the study of penetration of solids by the projectile million (Silvia, 1999. p. 69-70).

History of ballistics

Charles Waite considered father of forensic ballistics Opened private lab in New York City named

The Bureau of Forensic Ballistics in 1927. Phillip Gravelle and John Fischer were his

partners along with Dr. Calvin Goddard .

Calvin Goddard

In the late 1920’s, the work of Calvin Goddard brought the FBI (formally named in 1932) even more fully into the application of science to detective work.  Goddard, a pioneer in forensic ballistics, was instrumental in the opening of the Scientific Crime Detection Laboratory, then affiliated with Northwestern University, in Chicago.  The Bureau learned much from Goddard’s lab and it supported many of the efforts made by this organization over the next several years.

NYC Bureau of Forensic Balistics

In April 1925, the Bureau of Forensic Ballistics was established by C. E. Waite, Calvin H. Goddard, Philip 0. Gravelle, and John H. Fisher. The Bureau was formed to provide firearms identification services throughout the United States as few law enforcement agencies had the capability to provide this type of service. Goddard was very much a firearms identification pioneer who wrote and spoke extensively on the subject and was published in numerous publications. One significant event of particular note is that Gravelle adapted a comparison microscope for use in the identification of fired bullets and cartridge cases. This is considered by many to be a hallmark event in the science of firearms identification. Adapting the comparison microscope, for use in the examination of fired bullets and cartridge casings, allowed for a significant increase in the examiner’s ability to identify matching striations.

Valentine’s Day Massacre

During the height of prohibition, gang warfare raged over control of the illegal alcohol trade. One of the bloodiest battles was between Al “Scarface” Capone and George “Bugs” Moran. On Valentines night, 1929, seven of Moran’s men were awaiting a shipment of stolen alcohol. The shipment was actually a set up by Capone in an attempt to kill his rival, Moran. Moran was supposed to be at the warehouse but arrived late.

Valentine’s Day Massacre

Moran saw a “police car” pull up so he stayed back and watched. The “police” entered the warehouse and a barrage of machine gunfire was heard. Moran then saw the “cops” come out and drive away. The real police arrived and found each of the 7 inside shot numerous times. 70 casings were recovered from the scene. Bullets were later recovered from the victims.

Valentine’s Day Massacre

Goddard was called in and determined that the casings were from Thomson submachine guns. Using his comparison microscope, Goddard was able to prove that none of the PD’s guns were the murder weapons. Suspicion fell on Capone. Police later raided the home of one of Capone’s hit men and found two Thomson’s that were matched to the casings on the scene.

Capone and Moran

Bugs Moran on left

Al Capone

Fake Police arrive

Warehouse at 2122 North Clark Street where the ahil of .45 cal bullets were unleashed.

Diagram showing how the massacre may have happened.

Crowd gathers in front at 10:30 AM as the real police arrive

What was found inside

What was found inside

Bodies removed

Newspapers fall for the rouse

Bullet found in arms cache

Coroner, Goddard and others confer.

Bullets recovered from the bodies

Goddard and his comparison microscope

Modern Comparison Microscope

The guns today – on display

Discoloration from acid used to raise serial numbers ground off. Goddard could have looked inside the gun though. Click on bottom left picture to see Tommy in action

Sacco and Vanzetti In 1923, two Italian-American anarchists, Nicola Sacco

and Bartolomeo Vanzetti, were convicted of shooting a factory paymaster and his bodyguard to death in South Braintree, Massachusetts. The defendants' attorneys were seeking grounds for a new trial and called upon the services of Albert Hamilton. Since the Sacco-Vanzetti case had been grabbing headline for months, Hamilton eagerly got involved in the case.

Sacco's conviction has been based chiefly on the testimony of three firearms witnesses who said the bullet that killed the guard had been fired from his 32 caliber handgun. The experts also believed that the gun the police found on Vanzetti when they arrested him had belonged to the slain guard.

Sacco and Vanzetti

After examining the firearms evidence, Hamilton reported that the fatal bullet had not been fired from Sacco's gun, and the weapon in Vanzetti's possession was not the gun that belonged to the bodyguard.

Sacco and Vanzetti Relying on Hamilton's findings, the Sacco-Vanzetti

defense made a motion for a new trial. To counter this motion, the prosecution acquired the services of two new experts. In November, 1933, during the hearing for the new trial, Hamilton conducted an in-court demonstration involving two Colts and Sacco's gun. The new 32 caliber handguns belonged to Hamilton. In front of the judge and the lawyers for both sides, Hamilton disassembled all three pistols and placed their parts in three piles on the table. He then explained the functions of each part and demonstrated how they were interchangeable. After reassembling the handguns, Hamilton placed the two new weapons back into his pocket and handed Sacco's Colt to the court clerk.

Sacco and Vanzetti Before he left the courtroom, the judge asked

Hamilton to leave the new guns behind. Several months later, when the judge asked one of the prosecution firearms experts to reinspect Sacco's gun, the expert discovered that the barrel to Sacco's gun was brand new. Following an inquiry, Hamilton admitted that the new barrel on Sacco's Colt had come from one of his pistols. Although it was obvious to everyone that Hamilton had made the switch, presumably with a mistrial in mind, he denied it. Hamilton continued his association with the Sacco-Vanzetti defense, but he no longer played an important role in the case. He had destroyed his credibility as a firearms expert witness.

Sacco and Vanzetti

The Sacco-Vanzetti motion for a new trial was denied, and in 1927 the two men were executed. Prior to their death, Dr. Calvin Goddard, the most qualified firearms examiner in the world, stated that Sacco's gun had been the murder weapon. (Several modern firearms experts have examined the ballistics evidence in the case and agree with Goddard's findings.)

Sacco (right) and Vanzetti (middle)

It was a bold and outrageous pair of murders. Three o'clock in the afternoon - in broad daylight - two armed men shot and killed a paymaster and his guard. Seven shots in all were fired. The killers picked up the two boxes containing almost $16,000, leaped into a car containing several other men, a car that had pulled up with precise timing, and sped away. The whole audacious enterprise had taken less than a minute.

Firearms ID – Originally NOT a science

Albert Hamilton came into prominence in 1915 when he testified for the prosecution as a firearms expert in a rural New York murder case. The defendant was Charlie Stielow, a slightly retarded farm hand who was accused of shooting to death the couple who owned the farm where he worked and lived. Stielow was convicted of first-degree murder on the strength of a coerced confession and the ballistic findings of Hamilton who testified that a scratch inside the barrel of Stielow’s 22 caliber revolver had made a mark on one of the murder bullets. Having earned fifty dollars a day for his work on the case, Hamilton impressed the jury by showing them enlarged photographs of the fatal bullet.

Firearms ID – Originally NOT a science

Hamilton's testimony was pure hokum. The science of firearms identification as it is practiced today, did not exist in 1915. The comparison microscope, an instrument essential to the comparison and analysis of firearms evidence, was not invented until 1926. Nevertheless, Hamilton assured the jury that the fatal bullet had been fired from the defendant's gun. His findings went unchallenged, and no one seemed to notice that he hadn't even test-fired the so-called murder weapon. Charlie Stielow was found guilty, and sentenced to death.

Firearms ID – Originally NOT a science

Two years later, a pair of tramps confessed to the murder, and the Governor of New York formed a commission to review the case. Charles Waite, an investigator in the New York Attorney General's Office, was appointed by the commission to look into the matter.

Waite took Stielow's revolver to a New York City police detective who knew firearms. A thorough examination of the gun convinced the officer that Stielow's revolver hadn't been fired in four years. Moreover, a naked eye examination of the test-bullets showed vastly different barrel marks than those found on the murder bullets.

Firearms ID – Originally NOT a science

As a result of these findings, Charlie Stielow was pardoned, and Charles Waite went on to become a well-known firearms expert. In 1922, Waite formed the Bureau of Forensic Ballistics in New York City. The bureau, the first of its kind, was taken over in 1926 by Dr. Calvin Goddard an Army surgeon and ordnance officer from Baltimore who became the most prominent firearms identification expert in the world.

The Bullet.

Proper Technique

38 Caliber and 44 Caliber

How a bullet is fired

The bullet casing or shell is also marked or “striated” when it cycles through a gun. A firing pin striking the primer leaves a specific

mark in the back of the shell Commonly, a semi- automatic or automatic

firearm will eject the casing on its own immediately after being fired

The mechanism that ejects the casings will also create its own striations on the shell.

The Barrel rifling

Rifling and Striations Many modern guns have rifling in their barrels

The rifling adds spin to a bullet, causing it to travel straight.

Because the bullet fits the barrel exactly, the rifling of the barrel leaves marks, or striations on the bullet.

Since each gun is different, the marks a particular gun makes on a bullet shot through its barrel is unique, like a fingerprint.

Striations

Every gun leaves striations on every bullet and casing that travels through it. These striations are unique to each gun, no

two are exactly alike. These striations are like fingerprints that can

be compared and traced Obviously this is very helpful in identifying

what weapon was used in a particular crime

Lands and Grooves

Rifling patterns

http://www.firearmsid.com/Galleries/static/A_riflingIllustrations.asp

Comparison scope of lands and grooves match up.

What must be collected

Of course evidence must first be collected from the scene. Shell casings may be found on the ground

near where the shooter was standing Bullets may be found lodged in surrounding

items such as trees, walls, the ground, or they may be found still lodged in the victim.

If possible the gun may even be uncovered at the scene.

Compare their evidence

The evidence must now be compared to other evidence. Bullets and casings can be compared to

bullets and casings from other crimes or crime scenes using most often a microscope.

If a weapon is found or seized, scientists can test fire the weapon and compare these new bullets and shells with bullets and shells from the original crime.

Firing pin marks

Comparison micrograph of firing pin marks

Firing pin drag marks

Extractor marks

Ejector

Exhibit 1 (cartridge case) could neither be identified nor eliminated as having been fired by Exhibit 2 (firearm). The above conclusion is reached if the cartridge case

lacks sufficient action marks to be identified as having been fired by the questioned firearm or the firearm in question fails to produce reproducible individual characteristics on standards. 

Exhibit 1 (cartridge case) could neither be identified nor eliminated as having been fired by Exhibit 2 (firearm).All general class characteristics such as caliber and

firing pin shape would have to agree.  The image below shows a comparison between two cartridge cases that lack any individual characteristics but have a similar general appearance.

Watertank

Balistics Gelatin

used by the shooting industry to simulate soft body tissue, Ballistic Gelatin provides an alternative to live animal or cadaver testing. 

Exhibit 1 (cartridge case) was not fired by Exhibit 2 (firearm). This conclusion can sometimes be reached when the submitted

cartridge case exhibits very good individual characteristics that are very dissimilar to those produced on standards. 

• However, consideration must be given to the possibility that the firearm in question could have changed significantly. 

• If all dissimilarities can be accounted for, a negative conclusion

will be reached.  The comparison image below shows two cartridge cases that exhibit noticeably different breech marks and firing pin impressions.

Striae

The survey says…

Based on the results of these tests, scientists can now prove or disprove weather or not two bullets were fired from the same gun, or weather or not a gun fired a certain bullet.

This crucial evidence can often make or break a case in court, so long as it is presented in the right manner

Possible drawbacks

Shotguns and revolvers Bullet expansion and deformation No two bullets are EVER the same Barrels, along with the whole firearm can be

altered, switched, or destroyed.

GSR different in all weapons

Gunshot Residue - GSR GSR Pictures and bullet wipe http://www.firearmsid.com/Galleries/photo/GSR/a_gsrgal.asp

FBI Lab GSR Testing and pictures. The effect of hair and GSR

Gunshot Residue - GSR

Concentrated deposit of soot and vaporous lead residues.

Griess Test from the above 3-inch test standard.  Orange color is a positive reaction to a presence of a

pattern of nitrite residues.

Water tanks … preserve the bullet

In order to observe the striations in the bullets, scientists fire bullets into a tank of water.

The water helps preserve the striations left on the bullet from the gun used.

The scientist can then look at the bullet under a microscope and compare the striations to other bullets that have been used in a crime.

Striations

Striations – Lands and Grooves

Types of bullets A full metal jacket bullet is a bullet encased in

a copper alloy. A hollow point bullet is a bullet that has a

hollowed out shape in its tip. A frangible bullet is designed to disintegrate

into tiny particles upon impact to minimize their penetration.

A rubber bullet and plastic bullet are designed to be non-lethal, and are used in situations such as riot control.

Bullet types

Bullet types Bullet types and purposes Bullet type cross sections

Civil war bullets

Round projectiles – not accurate past a short distance. Gasses blowing by the round sice it was not a snug fit. To remedy this a cloth was added around the round to make up any gap that existed.

Cavitation

Shotgun Slug vs. Shot

Primers

Bullet in body – X-Ray

Entrance Vs. Exit wounds

Tibial “Butterfly Fx”

Tangential entrance

Hard contact wound

Near contact wound -

Powder tatooing

Shotgun Woundprevious pictures from Kevin J. Mahoney Forensics page http://www.relentlessdefense.com/gunshot.wounds.html

Near contact shotgun wound and spatter pattern.

Summary of wound types

General Features of Entrance Wounds a dirt ring around the wound caused by the bullet 'cleaning' itself

off on the skin as it passes through fibers may be found in the wound from clothing covering the wound a smaller defect than the diameter of the bullet due to elastic recoil of the skin. Powder blackening may indicate direction of fire (ex. a circular zone of blackening from a shot fired at right angles to the skin surface, compared to an oblique zone from an oblique shot etc) stippling/ tattooing of the skin charring of the skin entry wounds caused by shots fired at a distance. Entrance wounds into skull bone typically produces beveling, or coning, of the bone at the surface away from the weapon on the inner table. In thin areas such as the temple, this may not be observed. Sternum, iliac crest, scapula, or rib may show similar features. 

General Features of Entrance Wounds Tangential entrance wounds into bone may produce

"keyhole" defects with entrance and exit side-by-side, so that the arrangement of beveling can be used to determine the direction of fire. 

Use of silencers (or "muzzle brakes" to deflect gas and recoil) may produce atypical entrance wounds. A silencer is a device, often homemade, fitting over the muzzle that attempts to reduce noise by baffling the rapid escape of gases. Entrance wounds may appear atypical at close range.

General Features of Exit Wounds

A larger wound than the entrance wound, due to the bullet tumbling in it's passage through the body, and bony fragments being forced out through the skin can be of any size or shape, but are usually irregular (slit-like or square). May be similar to the entrance wound in size if the bullet was fired from a high velocity rifle shot at long distance (ex. a military rifle) a 'shored' exit wound occurs where the wound edges are abraded against an overlying object pressed firmly against the skin, as the skin is pushed out from the body by the bullet. The features were directly proportional to the KE of the projectile and the rigidity of the shoring material.

 

X-ray of .38 to skull

X-Ray of shotgun pellets to abdomen

CT of head showing boney fragments pushed in to brain area

9mm semi automatic

Revolver

Firearm Anatomy

Firearm Anatomy

How a weapon works

Remington’s website 3D images and applets of how the firearm works

http://www.remington.com/products/firearms/3-D/

How a revolver workshttp://people.howstuffworks.com/revolver2.htm

Pictures of all types of handguns

Firearms Illustrations

Bullet pictures

Bullet comparison micrographs

Cartridge casing comparison micrographs

Semi-auto rifle

Handgun vs. rifle bullet

Common types of rounds

Bullets after striking a target

Handgun Caliber Caliber is used to describe the size of a rifle or handgun bore

and the size of cartridges designed for different bores. Caliber is usually measured as the diameter of the bore from land to opposite land and is expressed in hundredths of an inch, thousandths of an inch, or millimeters. For example, a .270-caliber rifle bore measures 270/1000ths of an inch in diameter between the lands and has a larger bore diameter than a .223-caliber rifle. However, there is no standard set for designating caliber. In some cases, the caliber is given as the diameter of the bullet, which is the distance between the grooves. Caliber designations sometimes have a second number that has nothing to do with the diameter. For example, the popular .30-30 is a .30-caliber cartridge, but the second number is a holdover from the days when the cartridge took 30 grains of powder. The "06" in .30-06 refers to the year (1906) it became the official ammunition of the U.S. military. Circles show bore sizes of common cartridges. Having the same bore size does not mean different cartridges are interchangeable.

Handgun Caliber

Every rifle or handgun is designed for a specific cartridge. The ammunition must match the data stamp on the firearm. For example, there are several .30-caliber firearms that use the same bullet size but are designed for different cartridges (the .30-30, .30-06, .308, and the .300 Savage). If you cannot find the caliber stamped on the firearm, take it to a qualified gunsmith.

Handgun Caliber picture

Common Ballistic speeds

Chart of cartridge size and speed obtained when fired

Shotgun Gauge Shotgun gauges are determined by the number of

lead balls of a given diameter required to make one pound of that size ball. Thus 10 balls of 10 gauge diameter are required to make one pound of such balls, or 20 balls of 20 gauge diameter are required to make one pound, and so forth. This is the traditional, and very old, system. The actual (nominal) bore diameters of the various gauges are as follows: 10 gauge = .775 inch, 12 gauge = .729 inch, 16 gauge = .662 inch, 20 gauge = .615 inch, 28 gauge = .550 inch. The .410 is named for its nominal bore size, and is not a gauge at all

http://www.chuckhawks.com/intro_gauges.htm

Measuring Up: Gauge vs. Caliber Shotgun sizes have always been measured in a

somewhat roundabout way. You would think that the "12" in a 12-gauge shotgun corresponds to some linear measurement -- maybe inches or centimeters. But that's not the case. "12-gauge" means you can make 12 lead balls, each of equal diameter to the gun barrel, out of 1 pound of lead. This originated in the days when you would buy lead by the pound to make your own ammo. The gauge told you how many rounds you could make for the gun from 1 pound of lead.

Gauge sizing

Shotgun Parts

Making a barrel Creating a long, straight, consistent hollow tube that can stand

up to over 5,000 psi of pressure is one of the hardest parts of making a shotgun or rifle. First, a gunmaker takes a superstrong chrome molybdenum or stainless steel bar and uses a specialized gun drill to hollow it out. Unlike normal drills, most gun drills spin the steel bar instead of the drill bit. As the bit moves along inside the tube that guides its path, the machine shoots oil down the tube to clear the debris, lubricate the path and keep it cool. It takes about a half hour to drill out one barrel. This gets most of the work done, but the resulting hole is usually not large or consistent enough yet. A second machine reams out the last few thousandths of an inch and makes the diameter consistent along the whole barrel.

Shotgun vs. Rifle barrel

Choke types To control spread and impact point of shot

Shot Shell

Miscellaneous Ammo

Breaching rounds - Shotguns are commonly used in the military to "unlock" doors when troops don't know what lies on the other side. Because traditional ammo tends to ricochet and may end up hitting the shooter or someone inside the room, breakable "breaching rounds" are often used. These shells contain a metallic powder that disperses on contact.

Bean bags - Bean bags are used as shotgun ammo in crowd control situations, as in most cases they stun the victim but do not inflict lasting damage.

CS gas grenades - Combat shotguns can be used to disperse tear gas and similar chemicals.

Rock salt - Rock salt is a popular home defense ammunition because it reportedly causes severe pain but usually no permanent damage.

Alternative shotgun shells

Shotgun shell cross section

Shotgun Shot (pellet) sizing

Frangibles

Ammunition Illustrations

http://www.firearmsid.com/Galleries/static/A_AmmoIllustrations.asp

Cell Phone gun

Test fire video

The rifle is chambered for the .577 Tyrannosaurus Rex. 

According to reloading data, the 13.6 pound rifle

At a velocity approaching 2600 fps for a muzzle energy of over 11000 foot-pounds. 

This energy is comparable to that of the US military's .50 BMG cartridge frequently used as a heavy machinegun and anti-material rifle.

Ballistics PPT assignment

http://learngen.org/resources/leobjects/lg0044aa.html

The Dick Cheney Shotgun Experiment

http://www.myscienceproject.org/shooting.html

Alex Jones Chaney explanation and experiment

Dick Cheney ballistic test results

Gun Safety

Children should not play with guns

Sniper training school – terminal balistics

Shooting a bowling ball

Bud Dwyer shoots himself during press conference 5/9/1994