Handguns and ammunitions indicators extracted from the GSR analysis.

The computer automated scanning electron microscope. X-ray microanalysis of Firearms Discharge Residue (FDR) can reveal substantial information about the circumstances of their generation beyond the presence of characteristic gunshot residue (GSR). Indicators of the type of weapon and ammunition used can he obtained from the distribution of GSR particle shapes and from the multi-element analysis of the FDR sample. This is demonstrated for a large database of GSR samples from nine different handguns and over 60 different ammunitions. An example classification scheme is presented for the supporting particles generally found present in FDR. When particle type area concentration ratios are normalized to the iron (Fe) particle type, results show it is possible to distinguish much about the metal used in the weapon manufacture, whether it was of large or small caliber, whether the bullets were jacketed or plated, and whether the cartridge cases were of aluminum, brass, or nickel-plated brass. Standardization of such analytical schemes would be advantageous.