The article deals with some of the issues of forensic investigation of atypical firearms. The historiography, the prerequisites for the appearance of some samples of the weapons in question, their tactical and technical characteristics are disclosed, and a comparative description of the most interesting weapon samples from the point of view of the author is given. The stages of the study of atypical firearms are briefly formulated in this article. Forensic examinations of the said objects solve issues of both identification character and non-identification. In the process of their implementation, three main tasks are solved: the assignment of an object to an atypical firearm; its suitability for the production of a shot; the establishment of the presence or absence of identity and group affiliation.
In identification studies of atypical weapons, the expertʼs goal is: a) to obtain experimental maps of objects to be inspected under certain conditions; b) establishing the stability of an individual set of characteristics; c) identification of conditions for trace formation; d) identifying, explaining the causes and boundaries of variation of characteristics for inclusion in the identification set; e) elucidation of the mechanism of formation of traces on projectiles and sleeves for the determination of individual and persistent traces; f) elucidation of the influence on various traces of the formation of various factors. Summarizing the materials of expert practice allows us to classify the conditions that are verified during the expert experiment in the study of atypical weapons and shot marks: a) provided by the investigator, based on the circumstances established and the verified investigative versions; b) granted by the accused or the victim; c) determined by the expert by studying the design of the combat qualities of the atypical weapon in question and the marks of the shot. Summing up the foregoing, we can state that the crime situation has sharply deteriorated during the period of the ATO. One of the reasons is the influx of illegal firearms, including modern atypical weapons. All this takes place against the backdrop of the absence of the Law of Ukraine “On Weapons”, which would give the classification of firearms at the legislative level, as well as the inconsistency (obsolete) of some techniques for forensic research. At the methodological level, a number of issues of classification studies of modern samples of atypical weapons and methods for its production have not been resolved. We consider it topical to classify modern samples of atypical firearms by the method of manufacturing: industrial, artisanal, homemade; by purpose: combat, multi-purpose.