Identifying marks on Casings and GSR and Bullet

Identifying marks on Casings and GSR and Bullet Wounds

Cartridge Markings All moving components contact the cartridge rather than the bullet can leave useful impressions on shell cartridges – Breechface marks – Firing pin impressions – Chamber marks – Extractor & Ejector markings

Breech-back of barrel

Breechface Marks

Actual Breech Marks

Firing Pin Marks

Chamber Marks

Griess Test • Tests for the presence of nitrates (partially burned or unburned gunpowder) • Swab of shooter’s hand • Must produce a pattern for a distance determination

GSR on the hand of a suicide victim, proving he was holding the weapon when it was fired.

DANGER GRAPHIC IMAGES!

Contact Gunshot wound This is a contact gunshot entrance wound. Since the barrel contacts the skin, the gases released by the fired round go into the subcutaneous tissue & cause the star-shaped laceration.

Abrasion Ring The abrasion ring, and a very clear muzzle imprint, are seen in this contact range gunshot wound. An abrasion ring, formed when the force of the gases entering below the skin blow the skin surface back against the muzzle of the gun, is seen here in this contact range gunshot wound to the right temple.

With a contact or very close range gunshot wound, it is possible to have blood spatter as well as GSR on the hand of the person firing the weapon.