1. BALLISTICS

2. FIREARM IDENTIFICATION
A discipline mainly concerned with determining whether a bullet or cartridge was fired by a particular weapon

3. RIFLING
Lands and Grooves leave marks on bullets called Rifling

4. How is this Used to Solve Crimes?
The Striations (Lands and Grooves) of the bullets and casings found at the scene of a crime are compared under a microscope with that of a test fired bullet.
These are created when the barrel is rifled. No two gun barrels have the exact same markings.

5. Class Characteristics of Bullets
Different gun manufacturers use different rifling techniques, which impact the class characteristics of a bullet.
Number of lands and grooves
Width of lands and grooves
Depth of lands and grooves
Pitch
Twist
Right Twist
Left Twist

6. Class Characteristics of Cartridge Cases
Manufacture ( i.e.. Winchester)
Shape ( i.e.. rimless, rimmed )
Caliber ( i.e.. 45 ACP, 9mm, 12gauge)
Composition ( i.e.. brass, steel, plastic)