1. Identifying marks on Casings and GSR and Bullet Wounds

2. 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

5. Breech-back of barrel

6. Breechface Marks

7. Actual Breech Marks

8. Firing Pin Marks

9. Chamber Marks

10. 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

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

14. DANGER  GRAPHIC IMAGES!

15. 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.

16. 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.

17. 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.