a tracing mechanism

Introduction. One of the main ways to identify weapons in a forensic examination is to study the traces left on the cartridges. As a result of the examination, it is possible to receive answers to questions related to the model and a specific weapon. In this regard, information on traces and trace details for new models of firearms and the latest modifications of well-known models becomes relevant (manufacturers update the produced weapon approximately every 5–10 years). Experimental part. The experiment was carried out in the conditions of a shooting gallery; in total, about 200 rounds of 9×19 mm caliber (Parabellum) were shot from the following models of pistols: Glock 17, Glock 34, Beretta 92 FS, MP-446 Viking. Each model of the weapon was presented in three copies, for shooting of each copy no less than 10 cartridges were used, the case of the top cartridge in the magazine for 12 o'clock position was marked with white paint. Traces on the cartridge cases were examined visually and under a microscope with a magnification of 20× and 40×. Discussion of results. The trace pattern on the experimentally obtained spent cartridge cases corresponded mainly to the reference data. A trace from Glock 17 and Glock 34 was found at the bottom of the cartridge case from the tip of the striker that was not connected with firing-pin impression that is not listed in the reference book. This track has a large variation depending on the rate of fire (this is due to the different heating of the weapon). The trace from the front part of the ejector hook from Beretta 92 FS, that is not described in the reference book, was found at the bottom of the cartridge case at 4 o'clock position. The marks on the cartridge cases of the shotguns of the Viking MP-446 differ from the ones described in reference books by the presence of the traces of processing of the cartridge stop and the trace from the striker tip on the primer, which is not related to the cap of the primer, showing variability depending on the rate of fire. Conclusions. The obtained trace images of signs on the cartridge cases of modern modifications of the known models of firearms allow us to specify the definition of the model of the weapon according to group attributes. Using the data obtained, it is possible to identify the rate of firing of weapons at the scene of the accident in the absence of the weapon by following the tracks on the cartridges. The traces on the cartridge cases, that were obtained during the experiments and are not described in the literature on forensic issues, have individual characteristics and can be used for identification. The dependence of the trace formation on the rate of fire correlates with the recommendation for obtaining cartridge cases for a comparative study of a combined firearm: first, one should fire the cartridges in the single-fire mode, and then in bursts. For self-loading weapons, it can also be recommended to vary the rate of fire when experimentally obtaining cartridge cases for comparative research.