Bullet Trajectory
Notes on page 68-69
Welcome to
Ballistics!
Sharpshooter
You’ll enjoy this
one!
Parts of the Gun• Click to add text
Magazine
Trigger
HammerFiring 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• Hits the primer• Causes primer powder to spark• Spark goes through flash hole and ignites
rest of gunpowder
How a Revolver Works
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)
Land
Groove – the little lines etched in the grooves are the striations
What happens to evidence?• Cartridge cases
– Ejected from semiautomatic guns (usually to the right)
– Remain in cylinder in revolvers
Semiauto vs Revolver
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
Bullets - Individual!• Play video!
Cartridge Cases - Individual
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