Quiz#1 Lessons 1-5

Charles Waite, Col. Calvin Goddard, Phillip Gravelle and John Fisher developed the comparison microscope technique for the identification of weapons in the year

1925

THE GUN CONTROL ACT OF 1968 TITLE 18, UNITED STATE CODE, CHAPTER 44:

A ) any weapon ( including a starter gun which will or is designed to or may readily be converted to expel a projectile by the action of an explosive; (B) the frame or receiver of any such weapon; (C) any firearm muffler or firearm silencer; or (D) any destructive device. Such term does not include an antique firearm.

Firearms Identification

A discipline in forensic science which has as its primary concern to determine if a bullet, cartridge case or other ammunition component was fired from particular firearm (NIJ Firearms Examiner's Training).

A gun which discharges one shot with each pull of the trigger is

A semi-automatic.

The major difference between a rifle and a shotgun is the fact that_

A shotgun has no rifing.

Single Action Triggers

A single action trigger performs the single action of releasing the hammer or striker Single action firearms require that the hammer be cocked before the round is fired. Semi-auto pistol versus a single action revolver needs to be cocked for every shot.

Cartridge

A single unit of ammunition consisting of the case, primer, and propellant with one or more projectile(s). It's ammunition that is intact.

Shotgun:

A smooth bore shoulder firearm designed to fire shotshells containing numerous pellets or sometimes a single projectile (AFTE).

Define Firearm?

An assembly of a barrel and action from which a projectile is propelled by products of combustion

Berdan

Anvil is part of the cartridge case Two flash holes

Boxer primer

Anvil is seperate Single flash hole

Guns which operate on the ________ principle use the explosive force of the cartridge to load and fire the gun.

Automatic

A defective or damaged searnotch in a semi-automatic weapon may cause:

Automatic fire .

What is the name for the science of projectiles in motion

Ballistics

7 basic types of firearm" actions"

Bolt Pump/Slide Lever Hinge Semi automatic Fully Automatic Revolving

A barrel which has the same inside diameter from the front chamber to the muzzle is known as

Cylinder bored

1900 -1930

Firearms Identification becomes a science Knowledge "experts" had on firearms was largely personal No exchange of ideas through publications or societies

What is the principal ingredient of smokeless powder?

Guncotton

Two Primary Striking Mechanisms

Hammers and Strikers:

Types of Firearms

Handguns Long Guns

First Experts

Henry Goddard .Identified mold mark from a lead ball & paper patch

Those actions that occur before the bullet leaves the muzzle of the gun barrel are called

Interior ballistics.

Ninety-five percent of the cases coming to a firearms examiner's attention will

Involve modern weapons.

How does inertia affect the trajectory of a bullet?

It allows it to remain in motion.

The barrel reamer is used

Just prior to rifling.

Class Characteristics

Measurable features of a specimen which indicate a restricted group source. They result from design factors, and are therefore determined prior to manufacture.

Theory of Firearm (Tool Mark) Identification

No two firearms are identical. a Manufacturing process leaves random imperfections which are unique to that firearm Tools used in the manufacturing rocess are constantly changing as they cut, shape, etc. the firearm. The subsequent use, abuse & cleaning furthers the individuality

Non-jacketed bullets

Non-jacketed usually made of an alloy comprised of lead & antimony which is slightly harder than lead.

Actions vs. Trigger Actions

Not to be confused with a firearm's trigger action" or "firing mechanics" which refers to how many functions the trigger mechanism performs during the firing of the weapon.

Buffer

Plastic granules - protects shot charge & bore; filler

Shotguns (2)

Pump/Slide Action Autoloading

All rifles that are not single shot are known as

Repeating rifles

Single action, double action, ejection rod, break- open and solid frame are all terms that refer to

Revolvers

Handguns to main categories

Revolvers: and pistols

Long Guns Two main categories:

Rifle and long gun

The spinning motion of a bullet to provide better ac- is caused by:

Rifled barre

Hook-Cutter, Scrape-Cutter, Broaching, Button and Mandrel Swaging all systems used in

Rifling

Which of the following actions causes the shot string to be constricted?

Shortening the barrel.

In rural areas you are more likely to find

Shotguns.

Composition (5)

Solid Bullets Bullet Jackets Bullet Cores Bullet Coatings Sabots

Stielow Case 1915

Stielow sentenced to death Green (pleaded guilty to 2nd degree 20 years) Charles Waite Retrial & pardons

The potential force that a bullet exerts at any point in its trajectory is expressed as:

Striking energy at a given distance.

1907 Brownsville (TX) Prison Riot

Suspected rifles were sent to the Frankford Arsenal Weapons were identified by cartridge case markings

Non-Jacketed Two methods of manufacturing

Swaged (factories) Cast (sporters; reloaders)

In a semi-automatic, once the first round is cham- bered and the hammer cocked, the force necessary to extract and eject the spent cartridge case, chamber the next round, and cock the hammer is supplied by

The Cartridge explosion.

Two devices that may leave identifiable marks on a cartridge casing fired in an automatic or semi-auto- matic weapon are

The extractor and the ejector

Exterior ballistics deals with

The flight of the projectile.

What is yaw?

The wobble ofa bullet caused by uneven forces as it leaves the barrel.

Firearm Actions

To understand how a firearm works, it is first necessary to understand the firearm's action. The action is a group of moving parts used to load, fire, and unload the firearm.

The curved path that a projectile follows after leaving the muzzle in known as

Trajectory

Battery Cup

Used in all shotshells Two cup assembly Plain cup holds the priming compound Flanged cup contains the anvil

Physical Characteristics Bullets

Weight (grains) Composition Measured Jacket type caliber / diameter Color / finish Length Base construction Base shape Nose shape Cannelures

Proiectile:

an object propelled by the force of rapidly burning gases or other means

Gun:

any tubular device for projecting missiles

John E. Fisher

design & machine work

Wads

discs or cylinders of paper, felt or plastic

Firearms ID routine work in

investigations

Stonewall Jackson

killed by "friendly fire"

1864: Union Army General John Sedgwick

killed by confederate sniper at 800 yards

Philip O. Gravelle

microscopist & photographer

Caliber:

refers to the diameter of the bullet or the diameter of the barrel

Strikers:

spring-loaded firing pins that travel on an axis in-line with the cartridge eliminating the need for a separate hammer

Hammers:

spring-tensioned masses of metal that pivot on a pin when released and strike a firing pin to discharge a cartridge.

Centerfire cartridges must be

struck close to the center of the primer & with enough force

Derringers:

the generic term applied to a wide variety of very small, or large caliber, single or double barreled pistols be either muzzle or breech which may loading construction

Great satisfaction by preventing the

trial & conviction of innocent persons for crimes committed by another

MCL 750.222 defines a Firearm as:

weapon from which a dangerous projectile may be propelled by an explosive, gas or air. Firearm does not include a smooth bore rifle or handgun designed to shoot BB's not exceeding .177 căliber.

An examiner can then compare the microscopic marks to determine

whether markings found on the evidence are the same as the markings produced by the submitted firearm.

A cartridge combines _______ in one unit.

The bullet , powder and primer

The term terminal ballistics refers to

The effects of the impact of the projectile on the target.

Rimfire Cartridge:

The most simple form of modern cartridges

Bullet:

a projectile designed to be fired from a firearm

Jacketed bullets

have a lead core, and the outside covering is made of harder metals Copper, brass, copper-nickel, etc

With the button system, rifling grooves are

swaged in .

Firearm examiners and experts firmly established in

the US and abroad

when a bullet or cartridge case comes into contact with the harder metal of a firearm,

the unique microscopic marks are imparted onto the softer bearing surface of the bullet or cartridge case.

Col. Calvin H. Goddard

(father of firearms ID)

Double Action Triggers

A double action trigger performs the two functions of cocking and then releasing the hammer or striker Applies to both pistols and revolvers When applied to revolvers, the trigger also rotated the cylinder. Though this is technically a third action, it is correct to refer to the mechanism as double action

Rifle:

A firearm having rifling in the bore and designed to be fired from the shoulder (AFTE).

Revolvers:

A firearm, usually a handgun, with a cylinder having several chambers so arranged as to rotate around an axis and be discharged successively by the same firing mechanism (AFTE)

Any tubular device for projecting missiles through the use of gunpowder is called

A gun.

Pistols:

A handgun in which the chamber is part of the barrel (AFTE).

Cannelure

A knurled or smooth groove around the circumference of a bullet (non-jacketed & jacketed) or cartridge case. Purposes include: Crimping (a.k.a. crimping chancellery) Lubrication Classification

Rifles 3 kinds

Bolt Action Lever Action Auto Loading Pump/slide action Assault Carbines

Each one of these parts or tools have the ability to leave marks that are unique to that firearm:

Breech face Magazine Firing Pin Feed Ramp Rifling Slide Extractor Firing Pin Aperture Ejector

NYC Crime Laboratory 1925

Bureau of Forensic Ballistics

Class Characteristics FIRED CARTRIDGE

Caliber Breech face marks Extractor marks Ejector marks Firing pin impressions Chamber marks Magazine lip marks

Class Characteristics FIRED BULLET

Caliber Rifling Lands Grooves Twist L&G dimensions Weight Physical features

St. Valentine's Day Massacre 1929

Chicago 7 gangsters were murdered by suspects dressed in police uniforms Machine guns later found in the possession of a Michigan" gangster

Reducing the barrel diameter of a shotgun near the muzzle is known as

Choke boring

In an auto-loading rifle, the automatic action is limited to

Extracting , ejecting , loading and cocking .

An event that changed the world's perception of the establishment of a scientific crime laboratory occurred on

Feb 14 1929

In its narrowest meaning, ________ is the science by which one can determine whether a particular bullet was fired from a particular gun, or whether a particular cart-ridge case or shotgun shell was fired in a particular gun

Firearms identification

Centerfire

Firing pin strikes the cartridge in the center of the primer which crushes the priming mixture between the priming cup & the anvil of the primer

The advantage of a double action revolver is more rapid firing. What is the biggest disadvantage?

It is difficult to keep the sights aligned on the target.

Perhaps, the least scientific of all ballistic factors is:

Penetration

In the early 1900's, a photographic procedure for bul- let identification was developed by

Prof. Victor Balthazard.