Bullet Trajectory Notes on page 84-85

Parts of the Gun Click to add text Firing Pin Rifled barrel Hammer Magazine Trigger Hammer Firing Pin Rifled barrel

Anatomy of a Bullet Flash Hole

How is a Bullet Fired? Pull the trigger Hammer is pulled back Hammer is pushed forward Hits the firing pin which hits the primer Causes primer powder to spark Spark goes through flash hole and ignites rest of gunpowder

Individual or Class? There are class characteristics, but when you look at striations, bullets are individual evidence Cartridge casings are individual because of the extractor and ejector marks

Individual!

What happens to evidence? Bullets Shot forward with a given force Stop when sufficient force is acted upon it (hits something that slows it down, gravity pulls it down) Cartridge cases Ejected from semiautomatic guns (usually to the right) Remain in cylinder in revolvers

Important Forces Forward force of the bullet Downward force of gravity To some extent: Wind speed

Bullet Trajectory Trajectory: path of the propelled bullet

Determining Location of Shooter Need 2 reference points to make a straight line Bullet holes in an object such as a wall, window or furniture Bullet holes in a victim (entrance and exit count as two!) Straight line tells investigators that shooter was somewhere on that line

Trajectory