Conclusions
Gunshot residue was collected from four types of ammunition by discharging a firearm within 12 inches from white printer paper. Scanning electron microscopy was used to collect back-scattered electron micrographs of the GSR particles. Analysis of the particle size distribution revealed that particle frequency decreases exponentially with increasing particle diameter. No significant difference in particle size or shape was found between ammunition types.
Energy dispersive x-ray analysis was used in conjunction with EM to determine the chemical composition of the GSR particles. The x-ray spectra revealed that lead, barium and antimony can be found as unique identifiers of gunshot residue. However, only very few of the particles analyzed were found to contain barium or antimony. Because of the inconsistency of x-ray spectra obtained, no significant difference could be detected between the four ammunition types.