A Survey of Primer Residues Produced by Contemporary Powder-Actuated Tool Rounds and Their Relation to Gunshot Residue

Abstract

This study was conducted to determine whether or not residues produced by contemporary powder-actuated tools could be distinguished from characteristic gunshot residue (GSR) particles, which contain all three of the elements lead, barium, and antimony. In the first part of the study, 17 different types of rimfire powder loads were discharged and their residues analyzed by scanning electron microscopy—energy dispersive X-ray spectrometry (SEM/EDX). The residues from each of the powder loads consisted of lead/barium, lead, and barium particles. Two brands of fasteners were used in testing in the second part of the study. Both types of fasteners were made of steel and coated in zinc. Twelve trials were conducted, driving 10 fasteners each. Samples were collected from the hands of the powder-actuated tool operator at the end of each trial and analyzed by SEM/EDX. The residues on the tool operators' hands consisted of particles of lead/barium, lead, barium, and zinc. No significant incorporation of zinc into the lead/barium particles was observed. No characteristic lead/barium/antimony particles were observed. Some rimfire ammunition does not contain antimony in its formulation and the lead/barium residues from ammunition of this type cannot be distinguished from powder-actuated tool residue. The results demonstrate, however, that powder-actuated tool residue can be distinguished from characteristic GSR particles.