Experience with the method of autoradiography for firing distance determination

Abstract

Both the quantitative determination of antimony in the firearm discharge residue and the making visible of the residue pattern around the bullet hole play a role in the determination of firing distance. For a certain combination of firearm and ammunition, definite characteristic distributions arise from which the firing distance is calculable by purely visual comparison. When contamination is suspected, the autoradiograph plays a vital role. The stripping technique allows the carrier and residue to be separated without disturbing the characteristic distribution. This technique is indispensable when the carrier exhibits strong matrix activity. The method is in addition non-destructive, i. e. the targets remain intact as evidence.