Independent bulk elemental analysis was conducted on the residue from fired cartridges to trace the presence in the primer and bullet particles of various oxides, salts, and metals added to the cartridges before they were fired. All primers were the standard 'small pistol' primer, Winchester 1 and 1/2-108; cartridge cases were nonplated brass; and two .38-caliber and one 9-mm. common commercial cartridges were used in the experiments. Tracers were added to bullets by electroplating or solution-plating the bullet, while tracers were added to powder by dropping a weighed amount of the tracer compound directly into the case before the loading of each individual cartridge. Firings were conducted with the following additions to smokeless powder: rubidium sulfate, strontium sulfate, germanium, cobalt, and gold in elemental form. Results are consistent with the hypothesis that gunshot residue is formed by the condensation of vaporized bullet and primer materials that segregate into metallic and compound particles. Some of the metallic vapors are oxidized and 'scavenged' by oxygen and sulfur-rich primer compounds, among which the sulfur compounds appear to be more effective. The 'bullet' particles of the residue thus originate in the bullet material, and the 'primer' particles are a mixture of primer-derived and bullet-derived materials. Tables, figures, footnotes, and 14 references are provided.
On the Mechanism of Gunshot Residue Particle Formation
NCJ Number
69840
Journal
Journal of Forensic Sciences Volume: 25 Issue: 3 Dated: (July 1980) Pages: 533-545
Date Published
1980
Length
13 pages
Annotation
The mechanism of gunshot residue particle formation was investigated by conducting several experiments in which various materials were fired in cartridges, and residue particles containing these materials were determined.
Abstract