Forensics Vocab Quiz Chapter 15 Ballistics

caliber

the diameter of the bore of a firearm or the cartridge that it fires, expressed in hundredths of an inch.

• bullet sizes that is a measure of the diameter and expressed in inches.

bore

the interior diameter of a gun barrel

gauge

interior diameter of a shotgun barrel

• determined by # of lead balls of a size exactly fitting the barrel that are required to make one pound. 

shot

lead spheres in a shotgun shell

• aka lead pellets

slug

a single pellet/shot/bullet in a shotgun shell.

grains

basic units of weight in the british system; unit of weight for precious metals, gunpowder, bullets, and gemstones.

rifled

bore of a gun barrel in a form of a grooved spiral like a helix

lands

raised areas btwn 2 groves in the rifling of a gun barrel that impart grooves on a bullet

grooves

spiral cuts into the bore of a barrel that give a bullet its spin or rotation as it moves down the barrel

striae

parallel sets of scratches on a bullet caused by unique marking in the bore of a rifled weapon.

cannelures

grooves around a bullet that provides a means of crimping (compress) the cartridge case to bullet

head stamp

numerals, letters, and symbols on the base of cartridge showing the manufacturer, caliber, and code

breech

portion of the gun that contains the firing mech

extractor

hooked or crescent shaped part attached to breechblock which withdraws the spent casing from the chamber when the breechblock separates from the barrel after firing

ejector

part on the firearm whose function is to throw a spent casing from the gun after firing

magazine

container that holds cartridges under spring pressure to be fed into the gun’s chamber aka clip

chamber

part of the firearm that contains a cartridge for firing

griess test

color test for presence of nitrate in gunpowder residue

GSR

gun shot residue consisted of burned & unburned powder, vaporized and particulate lead, prime residues of lead, barium, and antmony

sodium rhodizonate test

color test for the presence of lead in gunshot residue

buffer

solution containing a weak acid and its salt or a weak base and its salt, resistant to changes in PH.