AFTE Store - Back Spatter From Auto Windshield Glass

The most common procedure for determining range of fire in firearms examination is by analyzing the powder residue distrubution pattern on the target surface and comparing this to test fires from the same weapon with the same ammunition. If the target surface is destroyed during the assualt or the powder residue lands on a surface where it cannot adhere, then a firearm-to -target measurement cannot be calculated. This is what happens when a shot is fired at a victim through automobile glass. Because of tempered glass manufacturing characteristics, side windows will shatter and fall out destroying an pwder residure left behind. A shot fired at the front or rear windshields wil not leave any residue if the car is in motion during the shooting or the vehicle is towed back to the forensic laboratory for examination. Rather than examining the powder residue left on the target surface, what about the glass fragments generated by the impact of the projectile? If it could be determined how far glass particles travel when a bullet impacts the glass, then perhaps some determination could be made on where the shooter was in realtion to the vehicle. An experiment was conducted to see if different bullet velocities would produce glass fragment distrubutions of known distances. Once these distance are calculated, any person with glass fragments found in their clothing would be suspected of being in close proximity to the window when it was fired upon.