Specifics of gunshot residue deposition when using “Fort 9R” and “Fort 17R” pistols at different distances

Abstract

Identification of the distance of the shot, the weapon of the shot, and other circumstances in the case of a gunshot injury are among the key issues facing the forensic medical expert and of greatest interest to law enforcement agencies. The world standard for answering such questions is the use of laboratory instrumental methods for the identification of the gunshot residue – microparticles that fly out of the barrel of a weapon when a shot is fired. However, for the successful application of this knowledge in practice, it is necessary to perform preliminary experimental shootings. The least researched at the moment are samples of non lethal firearms, which, despite their name, can lead to lethal consequences and are becoming more and more common among the civilian population. The purpose of the study was to investigate the peculiarities of the deposition of the residual components of the shot when using the Fort 9R and Fort 17R pistols at contact range, 25 and 50 cm distances. A controlled ballistic experiment was performed in shooting range conditions on 120 gelatin blocks made according to the generally accepted method, which were subsequently covered cotton fabric, denim fabric, leatherette or left bare. The shots were fired from Fort 9R and Fort 17R pistols at contact range, 25 and 50 cm. After the shots, a chromato-mass spectrometric study and infrared microscopy on a combined IR-Fourier spectrometer were performed to detect gunpowder components and X-ray fluorescence spectroscopy to detection of overlays of elements on the trace-receiving object. Statistical processing of the received data was carried out in the license package "Statistica 6.0". The obtained data indicate the existence of numerous reliable differences in the indicators of overlap on the trace-receiving object of lead, iron and zinc, which allows them to be used for the identification of the shot tool and the shot distance. In addition, specific features of the deposition of elements on different clothing materials and bare blocks were revealed, which are most evident in the analysis of blocks covered with leather substitute. Among trace elements, zinc has the greatest practical value, while copper has no practical value in the analysis of shots fired from Fort 9R or Fort 17R pistols. Residual components of gunpowder in the case of the use of these pistols are of limited value and have been detected in some cases when fired at contact range and 25 cm on bare blocks, blocks covered with denim or leatherette.