Forensics: Basllistics

The job of the firearms examiner involves examining

used bullets and their spent casings for telltale markings left on them by a specific firearm.

A firearm is a

portable gun capable of firing a projectile using a confined explosive.

Rifles fire bullets, while shotguns can fire either

small, round pellets or a single projectile, called a slug.

The tangent of an angle in a right triangle is equal to the opposite side (b) divided by the adjacent side (a). This information, from the law of tangents, can be used to determine

the trajectory of a bullet.

The path of flight of a projectile is its

trajectory.

Muzzle -

The end of the barrel, where the projectile exits a firearm

The earliest firearms were

matchlock weapons and had wicks to carry a flame to the gunpowder.

Matchlock weapons were replaced by flintlock weapons, which used

sparks from a chip of flint to ignite the gunpowder.

The word, rifle, originally referred to the

grooves, or indentations, in the rifle's barrel.

The term, bullet, is often incorrectly applied to the

cartridge, which includes primer powder, gunpowder, the bullet, and the casing material that holds them all together.

Bullets and their cartridges are named by

caliber nor length

A .45-caliber bullet has a diameter of

about ½ of an inch.

To get a known bullet for comparison, investigators test-fire the weapon into a

water tank or gel block

Firing pin marks left on spent cartridge casings can also be used to identify a firearm. Firing pin marks are impressions made

on the bottom of the cartridge casing when a bullet is discharged.

Breechblock marks are produced as the cartridge casing moves

backward against the breechblock.

Generally, entrance wounds are ______________ than exit wounds.

smaller

Firearms databases can be searched to match crime scene projectile evidence to

registered images of markings from previous crimes.

A _____________ is not a rifled weapon

shotgun

The trajectory of a projectile is

the path of the flight of a bullet

A barrel is

not part of a cartridge

The caliber of a bullet is related to its

diameter.

Rifling in a gun barrel makes a bullet fly

straighter.

A contact wound shows a

star pattern.

Brand, metal composition, and color are all

class characteristics of a bullet.

A moving projectile has kinetic energy that is

proportional to its mass and velocity.

Pellet balls are released

from a shotgun

NIBIN is

the database for firearms

The Griess test

determine gunshot residue.

The right to keep and bear arms is

protected by the second amendment to the constitution