Investigation of the quantitative change of firearms shot residue due to the number of shoots and different bullet types.

Organic and inorganic residues (typically Antimony, Barium, Lead), called gunshot residues (GSR), provide valuable information in terms of illuminating the incident in crimes committed with gunshot. Although there are many studies in this field, applications and researches to determine how many times the suspect fired with a gunshot are limited. In this study, inorganic gunshot residue concentrations accumulated on the shooting hand after consecutive shots at the indoor shooting range with different brands of bullets using Canik S/120 model semi-automatic pistol were investigated and analyzed by spectrometry (ICP-MS) method. Evaluation of the quantitative findings obtained was carried out with multiple regression model (MLR) and correlation analysis, and an MLR model was developed, which allows the estimation of the number of shots depending on inorganic gunshot residue concentrations. In this study, it has been determined that there is a linear relationship between consecutive serial shots made with 3 different types of bullets and the inorganic gunshot residue obtained from these shots. Considering the other factors affecting the retention of the shot residue, it is foreseen that the relationship obtained from this study will be revealed in a more concrete way and will take its place in routine practice, thanks to the studies to be carried out in different ambient conditions and with a larger number of bullet types.