DEPOSITION OF GUNSHOT RESIDUE WHEN FIRING «FORT 12R» AND «AE 790G1» PISTOLS

Abstract

The key element of pre-wound ballistics, which is of particular interest to forensic experts and criminologists, remains the residual components of the shot, represented by small spheroids. And although classically the greatest attention is paid to the so-called «forensic ballistics whales» such as stibium, lead and barium, the very ratio and presence of other trace elements plays an important role in the ability to identify firearms and other circumstances that may be of interest to the police.
 Aim of the work. To determine the peculiarities of the deposition of the residual components of the shot, namely, microelements on the tracer object when fired from «FORT 12R» and «AE 790G1» pistols from contact range, 25 and 50 cm.
 Materials and methods. 120 gelatin blocks were produced, divided into two groups of 60 blocks each, to be fired from the «FORT 12R» and «AE 790G1» pistols. Within each group, subgroups of 15 blocks are formed depending on the covering material, namely: bare blocks, blocks covered with cotton fabric, denim fabric or leatherette. The blocks in each subgroup were to be shot from different distances: contact range (5 blocks), 25 cm (5 blocks) and 50 cm (5 blocks). After firing, X-ray fluorescence spectroscopy was performed to determine the elemental composition, chromato-mass spectrometric method, and infrared microscopy on a combined IR-Fourier spectrometer to identify gunpowder components. The obtained indicators were subjected to statistical processing in the «Statistica 6.0» program.
 Results. The largest number of reliable differences was found in the study of the deposition of such elements as lead and iron, a smaller number in the analysis of zinc, and in the analysis of copper, no differences between the studied groups were found; when analyzing the components of gunpowder, it was established that they are mostly present when contact shots are fired from the «AE 790G1» to the blocks covered with denim fabric.
 Conclusions. The revealed numerous reliable differences between the studied groups regarding such elements as lead, iron and zinc allow them to be used for the purpose of further identification of the distance of the shot and the weapon.