Determination of Shooting Distance from Deformation of the Recovered Bullet

Abstract

Abstract A method is reported for estimating shooting distance by comparing the amount of bullet deformation of a recovered bullet with that produced in a series of test bullets fired into 10% ordnance gelatin at 4°C. Bullet deformation and fragmentation pattern in this gelatin was previously found to be comparable to that seen in living animal muscle. Striking velocities of the test bullets were lowered stepwise until a test bullet was produced with less deformity than the evidence bullet. Two shots were then made through the abdomen of a fresh swine cadaver at velocities approximating those of the last two test shots in gelatin. This served as verification of the gelatin's calibration against animal tissue and gave an additional set of bullets whose degrees of deformation bracketed that of the evidence bullet. Separate interpolations were done for bullet length, average bullet tip diameter, and bullet weight using both sets of bracketing test bullets. The resulting velocities were then converted to distances using the manufacturer's velocity tables. The average of the interpolations was 256 yds (234 m); all six fell within a range of 33 yds (30 m) (from 238 to 271 yds [218 to 248 m]).