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

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 (7.62 mm x 39 mm) on 1 mm sheet metal. 1 mm 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 1 mm 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

A forensic-based study on low angled AK rifle bullet entry wounds using a porcine model

An entry wound normally carries more macroscopic evidence than found in exit wounds. In addition to common wound characteristics of an entry wound such as an abrasion collar, burn marks etc., large amounts of trace evidences from the bullet and gun such as gunshot residues, powder tattoo, grease ring (bullet wipe) etc., are also present in entry wounds making them a richer source of evidence than exit wounds. This forensic-based study explores the low-angled entry wound characteristics of AK rifle bullets (7,62 mm × 39 mm) on porcine skin. This demonstrated a special entry wound characteristic similar to the commonly reported “abrasion ring” but differs in structure with an abraded area around the entry wounds and more significantly damaged outer margins. A significant inverse relationship between the AK bullet's approaching angle and the length of the external entry wound has also been reported in this work, with each finding contributing new knowledge to the forensic pathology of gunshot wounds. The findings of this study also have the potential to aid in shooting incident reconstructions

Post-blast histological changes to three animal bones exposed to close-range chemical detonation

A range of investigative practices to aid explosive-related death investigations currently exist, although the use of histopathological bone samples to diagnose blast exposure and the distance of individuals from the blast source has not been previously reported. Forensic histopathology has been used effectively on soft tissue samples to define blast-related injuries effectively, analysing human organs such as the lungs, brain, liver, and skeletal muscles, providing important and useful forensic pathology interpretations. However, no studies currently exist examining the post-blast histological changes in human or animal bones subjected to blasts for forensic pathology practice, despite the opportunity that hard tissue bone samples present, given their significantly lower rate of decomposition over soft tissue. This study presents the first evidence-based findings on the post-blast histological changes in three animal bones when exposed to close-range chemical detonation (C4). The study's qualitative findings highlight critical changes in the tissue architecture of three different animal bone sources due to blast effects with range from the blast source. This emphasises the potential use of histopathological bone sample analysis in future blast-related death investigations, while providing ideas to further explore this work using larger-scale experiments and post-blast case studies in aid of applying this work to human samples and forensic pathology practice