Ballistics The study of bullets and firearms Firearm

Ballistics The study of bullets and firearms

Firearm A weapon, such as a gun, capable of firing a projectile using a confined explosive

Types of Firearms 1. Long guns Rifles: fire bullets Shotguns: fire small round pellets (shots) or slugs 2. Handguns Revolvers: hold 6 cartridges Semiautomatic: load up to 10 cartridges in a magazine clip

Bullets

Cartridge = bullet + case + gunpowder + primer Caliber = measure of diameter of cartridge. 45 -caliber = 45/100 of an inch

Bullet Basics Materials: Lead Copper Brass Bronze Steel Aluminum Jacketed Bullets (travel faster): Non-jacketed Bullets:

Rifling Grooves cut or formed in a spiral down the barrel of a firearm Increases accuracy and range

Types of marks Rifling pattern Breech mark Firing pin impressions Extractor mark Ejector marks

Firearms Evidence Firearm Fired bullets Spent cartridge cases Spent shot shells Shot shell wadding Live ammunition Gunshot residue (GSR) Clothing

Firearms Examiners will: Test firearms Test for gunshot residue to determine distance from muzzle to target Determine caliber and manufacturer of ammunition components Match bullets or cartridge casings to firearms

Bullet Identification 1. Obtain standard from firearm 2. Compare crime scene bullet to standard using comparison macroscope 3. Unique marks made by imperfections or irregularities = individual evidence

Firearms Database NIBIN: National Integrated Ballistics Information Network n n n Database of images Ballistics markings of firearms used in previous crimes Cartridge casings

Bullet Trajectory Wind shield Distance along path of bullet to window, 23. 9” Path of bullet x y 60 feet Horizon Distance along horizon to window, 23. 5”

Bullet Wounds Generally, entrance wounds and smaller than exit wounds Entrance: skin stretches when bullet enters body Exit: bullet carries body tissue and bone with it Other signs: fibers in wound, GSR, stippling (burnt skin) Pass through: larger bullets, high-speed bullets

Gunshot Wounds