Deterioration of various cartridge case compositions in selective environments.

Abstract

Firearm and toolmark analysis has, as its primary function, to determine if a particular ammunition component was fired in, by, or from a particular firearm. Examiners in this discipline can be presented with components that have deteriorated over a period of time. This research sought to determine the likelihood of identification over time, the possibility of establishing a timeline based on different variables, and effectiveness of three restorative techniques, to aid examiners when dealing with corroded cartridge cases. This study includes several variables not tested in previous studies to add to the existing literature. Results indicate that the likelihood of identification is affected by time, firearm used, and cartridge case composition. Scanning electron microscope (SEM) data analysis suggests that a timeline may be possible, but a more extensive study is needed. In addition, the effectiveness of the three restorative techniques appear to be dependent on cartridge case composition, but statistical analysis indicates that Aqua Regia was the most effective reagent for steel cartridge cases.