Investigating the Effect of Changing Ammunition on the Composition of Organic Additives in Gunshot Residue (OGSR)

Abstract

The measurement of the organic additives in smokeless gunpowder is an attractive approach for the detection of handgun use because it provides compositional information that can help associate residues and unfired gunpowder. We investigate several factors that will be required to advance the characterization of organic gunshot residue (OGSR) as a useful forensic tool, including evaluating residue contamination from previously fired ammunition, particle-to-particle compositional variability, and compositional features resulting from the type of firing primer used. Using ammunition loaded with known smokeless powders containing different stabilizers, a sequence of shots was fired from a .357 magnum revolver, and the muzzle exit residues were collected. Compositional analysis of the residues, both in bulk and as single particles, showed only a trace of the previously fired powder in the first shot and none in subsequent shots. In an additional experiment testing conventional leaded and the new lead-free firing primers, the OGSR composition was found not to depend on the primer type.

Recent developments in methods of chemical analysis in investigations of firearm-related events

“…Similar to Andrasko, MacCrehan et al found that compositional analysis of the propellant provides information that can associate residue samples with unfired gunpowder [89,90,91,92]. It was reported that qualitative identification and quantitative determination of additives in gunpowder enabled calculation of a numerical propellant (NG) to stabilizer ratio (P/S) that might be a useful index in associating handgun-fired gunpowder residues with unfired powder.…”

“…MacCrehan et al [56,57,88,89,90,91,92] used MECE for analysis and comparison of fired and unfired propellants. Procedures for recovery of gunpowder residue components under a variety of sampling conditions were evaluated and improved for MECE analysis.…”

Recent advances in the applications of CE to forensic sciences (2001–2004)

“…MEKC analysis of the organic additives in smokeless gunpowders was also used by McCrehan et al to evaluate residue contamination from previously fired ammunition. Compositional analysis of the residues showed only trace of the previously fired powder in the first shot and none in the subsequent shots [62]. Also, MEKC was used to test a new method for organic gunshot residue collection by hair combing.…”

Advances of capillary electrophoresis in clinical and forensic analysis (1999-2000)

“…MacCrehan and co-workers have pioneered the development of CE for the detection of organic gunshot residue and smokeless powders. In a series of papers they have demonstrated the applicability of CE for the detection of smokeless powder residue from pipe bombs [41], and gunshot residue [42][43][44]. These papers consist of a series of different validation studies of the analysis of smokeless powders.…”