Unit: Firearms, Tool Marks and Impressions Evidence

What is Ballistics?

the science of the travel of a projectile

in flight. The flight path of a bullet includes: travel

down the barrel, path through the air, and path

through a target.

Bullet Injury

1. Laceration and crushing - Low velocity bullets,

as in handguns, do virtually all their damage via

crushing.

 2. Cavitation - Significant with projectiles travelling in

excess of 1000 fps. A "permanent" cavity is caused

by the path of the bullet itself,, causing the wound

cavity to be stretched outward.

 3. Shock waves - Shock waves compress the

medium and travel ahead of the bullet, as well as to

the sides, At high velocity, generated shock waves

can reach up to 200 atmospheres of pressure.

Which term describes a complete unit of ammunition that includes the bullet, casing, primer, and propellant?

Cartridge case

What material is found inside a bullet recovery tank?

Cotton, Gel, Water

Describe caliber:

Inter bore of the of the gun caliber, Diameter of a bullet projectile, Interior diameter of the barrel of the firearm

Which two units of measure are weapons made in?

Inches, Millimeters

The spiral lands and grooves insid ethe barrel of a frime arm are called:

Riffling

The instrument used to compare bullets and match striations is a specialized instrument called:

Comparison Microscope

Where are bullets loaded in a firearm?

Chamber

In a shotgun case, what does it have that is not in in a handgun or rifle

Wad

What has to be struck in order for a bullet to be fired

Primer

Tool marks are encountered most frequently in ________ cases but may also be found in other types of crimes

Tool marks are encountered most frequently in _________cases but may also be found in other types of crimes

burglary

Visible two dimensional marks formed from soil, dust, paint, blood, ink, etc

Patent impressions

Three dimensional imprints left in pliable materials such as snow, mud, soil, or soap

Plastic impressions

What could a car run over to leave plastic tire impressions?

Snow