Physical Methods Exam 3

Firearms

determines whether a bullet/ cartridge was fired by a particular weapon

Firearms analysis involves

bullet comparison, restoration of serial numbers, distance estimation, and identification of gunpowder and primer residues

Ballistics

The study of a projectile in motion

Two groups of firearms

Handguns and shoulder fire gunsare the main categories of firearms, each serving distinct purposes and functionalities.

Firearm Barrel Categories

Smooth Bore and Rifled Bore

Rifling

imparts spin upon the projectile, resulting in improved accuracy

Lands

Raised areas on the bullet caused by grooves in the bore of the gun

Grooves

Indentations on the bullet caused by lands in the bore of the gun

Class evidence

The number and direction of the twist are gun manufacturer characteristics

Caliber

The internal diameter of the barrel

The larger the caliber, the wider the bore of the barrel and the larger the bullet needed to fill the bore

Guage

The term for diameter used for shotguns

Rifling Class Characteristics

Same number of lands and grooves and same approximate width and direction of twist

Rifling Individual Characteristics

Striation markings

Cartridge composition (rifles and handguns)

Primer, gunpowder, bullet

Shotgun shell composition

[Bore-size projectile (slug), pellets of large shot, or many tiny pellets (BBs)], gunpowder, primer

Ballistics

the study of a bullet in motion

Internal Ballistics

events that transpire within the firearm

External ballistics

events that occur after the bullet leaves the barrel of the gun but before it strikes its target

Terminal ballistics

what happens when the bullet strikes its target