A fired bullet and cartridge case

A fired bullet with rifling impressions from the barrel of a gun (left). A fired cartridge case and fired bullet (right). Experts can often identify the weapon used based on rifling impressions on the bullet, or breech face and firing pin impressions in the primer at the base of the cartridge case.

Cartridge case terminology and identification – Stephen Taylor, WW2 Relic Hunter

Projectiles AND Cartridges - Forensic's blog

Forensic Ballistics

How Good a Match is It? Putting Statistics into Forensic Firearms Identification

ELEY No 12 GAS TIGHT - General Ammunition Discussion - International Ammunition Association Web Forum

Bullets First Manufacturing

Fired bullet hi-res stock photography and images - Alamy

What are the Basic Parts of Ammunition

Bullets First Manufacturing

Shotgun and rifle cartridges