Forensic based empirical study on ricochet behaviour of Kalashnikov bullets (7.62mm×39mm) on 1mm sheet metal

Abstract

ABSTRACT: Bullet ricochet off a surface in a shooting scene occurs in diverse conditions and affected by array of factors. Therefore ricochet analysis of a particular incident demands case by case analysis supported by the knowledge of existing subject knowledge and empirical testing. In this view, existing empirical test results on bullet ricochet experiments have become always assisted and referred by investigators during scene reconstruction and in Courts. This forensic based research was aimed to understand the ricochet behaviour and related aspects of Kalashnikov bullets (7.62mm×39mm) on 1mm sheet metal. 1mm sheet metal was selected as the target surface of the study, based on its greater possibility of existing in concurrent urban environments as vehicle bodies, electrical appliances, road signs, boundary walls, partitions, walls of mobile houses etc. The research added brand new knowledge to the firearm investigation field in general and specifically to AK shooting investigations and scene reconstruction. The ricochet angles and critical angle of 1mm sheet metal and AK bullets, relationship of different impact feathers and angle of incidences are some of the main findings of the research. The double head impact mark which produces as a result of bullet's interaction with the target and it's specific relationships with the incident angles is the other most important results of the research which has not reported so far in a bullet ricochet study. In addition to the contribution of knowledge to the field of forensic sciences in general and forensic ballistic in particular, this research further emphasises the need for case by case empirical study to understand the ricochet behaviour of different bullet and target combinations. On the other hand, this study very deeply convinced firearms investigators on the risk of applying general bullet ricochet theory on yielding and nonyielding surfaces to reconstruct all bullet ricochet incidents which would result in wrong interpretations, critical errors in shooting scene reconstruction and finally for false testimonies. KEYWORDS: 1mm sheet metal; 7.62×39mm AK; Bullet; Bullet ricochet; Forensic ballistics; Shooting incident reconstruction.