NCJ Number
195244
Journal
Journal of Forensic Sciences Volume: 47 Issue: 2 Dated: March 2002 Pages: 260-266
Date Published
2002
Length
7 pages
Annotation
This research evaluated the powder and residues from commercial ammunition with cartridges that were given a coded identity.
Abstract
Qualitatively identifying and quantitatively determining the additives in smokeless gunpowder to calculate a numerical propellant to stabilizer (P/S) ratio is a new approach to associate handgun-fired organic gunshot residues (OGSR) with unfired powder. In past work, the P/S values of handgun OGSR and cartridges loaded with known gunpowders were evaluated. In the current research, gunpowder and residue samples were obtained from seven boxes of commercial 38 caliber ammunition with the goals of associating cartridges within a box and matching residues to unfired powders, based on the P/S value and the qualitative identity of the additives. Gunpowder samples from four of the seven boxes of ammunition could be easily differentiated. When visual comparisons of the cartridge powders were considered in addition to composition, powder samples from all seven boxes of ammunition could be reliably differentiated. Handgun OGSR was also collected and evaluated in bulk as well as for individual particles. In some cases, residues could be reliably differentiated based on P/S and additive identity. It was instructive to evaluate the composition of individual unfired gunpowder and OGSR particles. The researchers determined that both the numerical centroid and dispersity of the P/S measurements provided information for associations and exclusions. Associating measurements from residue particles with those of residue samples collected from a test firing of the same weapon and ammunition apparently is a useful approach to account for any changes in composition that occur during the firing process. 2 tables, 3 figures, and 15 references