This is the Final Summary Overview of the findings and methodology of a project that experimentally controlled the extrinsic variables of weapon, shooter, distance, caliber, and velocity in examining gunshot wounds on donated human heads, with the primary variable tested being the effect that bullets of two different constructions, jacketed hollow point (JHP) compared to full metal jacket (FMJ), have on human skulls.
Following fracture analysis, all skulls were photographed in detail, and an atlas with the photographs and all relevant variable information was developed. The atlas is available on request by members of the forensic science community to aid practitioners with skeletal gunshot-wound interpretation. A total of 45 donated human heads were obtained from an anatomical gift company, specifically for the purpose of trauma research. A total of 23 skulls were of females and 22 were of male. The skulls arrived fleshed and frozen and were defrosted to room temperature the night before the experiment. Each head was shot once either in the frontal or parietal/temporal bone region by an expert marksperson, using a revolver with a 1 7/8-inch barrel loaded with 0.38 caliber bullets. Each shot was taken from 3 yards. Bullet type was distributed randomly yet evenly between individuals. All statistical analyses were conducted using IBM SPSS software. Measurements were taken for exit wounds and bullet type, bone mineral density and cranial bone thickness, area and perimeter of entrance wounds, entrance and exit wound diameters, bullet mass loss, and bullet type prediction from quantitative and qualitative variables. The most substantial finding is that bones struck by JHP and FMJ ammunition of the same caliber can be distinguished based on the diameter of the entrance wound, with wounds caused by JHP bullets being significantly larger. 3 references