Tattooing in entry wound of a firearm injury is due to:
Effects of different discharges from a gun: Fire / Flame -- burning at entrance wound along with burning or singeing of hairs. Smoke - Blackening effect or smudging Hot gases- Scorching effect Unburnt Gun powder - Tattooing effect, peppering or stippling effect Felt wad - Minor abrasion and bruise. Bullet / Pellet - Puncture wound with abrasion collar.
Burns
Smoke
Gunpowder
Wads
Ballistics