Browsing by Author "Nishshanka, B."

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AK bullet (7,62 × 39 mm) ricochet off flat, wooden targets; A forensic- based study
(2021) Nishshanka, B.; Shepherd, C.
The ricochet behaviour of AK bullets (7,62 × 39 mm), one of the prominently reported bullet type in recent shooting incidents worldwide, has been examined on a range of different wooden surfaces in this study. The critical angles of AK bullets for teak, Jack wood, mahogany and pine were reported with close values ranging from 9.9 to 13.3- degrees, suggestive of being a valuable reference that can be used during AK bullet ri cochet-related shooting investigations with similar conditions. The study also highlighted a significant phenomenon against the existing understanding on the wood hardness and the critical angles of bullets. The widths of the AK bullet wipe marks generated on the wood surfaces were highly consistent, regardless of impact angle, allowing an effective approximation of bullet caliber. Bullet tunnelling effect were also observed with pinewood samples in this study. The study also further highlights the great variability of bullet ricochet phenomena and the challenging nature of using the theoretical and experimental results relates to wood ricochet studies for shooting reconstructions.
An empirical study on the close-range post-ricochet orientation of AK bullets (7.62 mm × 39 mm)
(Science & Justice, 2022) Nishshanka, B.; Shepherd, C.; Koene, L.; Punyasena, M.
Most of the injuries and deaths from ricocheting bullets in shooting incidents are usually reported due to misaimed shots that had ricocheted close to the victims. Although the destabilisation of ricocheted bullets during their ricochet flights is a generally known phenomenon, no significant quantitative-based scientific studies have attempted to understand bullets’ post-ricochet orientations at close distances. This empirical study explores close-range post-ricochet orientations of AK bullets (7.62 mm × 39 mm) on a range of domestic surface types typically encountered during bullet ricochet incidents. This study has revealed that ricocheting AK bullets off of various wood types and tile samples produce side-on impacts into closely located targets following a rightwards yaw action. It has also been shown that AK bullets ricocheting off concrete and cement samples at 5-degree incident angles produced nose-forward impacts on paper witness screens, similar to an orthogonal impact of a direct-fired shot. The findings present important new information on the post-ricochet yawing behaviour of AK bullets, which has the potential to aid future shooting reconstructions in which victims are hit by closely ricocheted bullets.
Forensic based empirical study on ricochet behaviour of Kalashnikov bullets (7.62mm×39mm) on 1mm sheet metal
(Elsevier, 2020) Nishshanka, B.; Shepherd, C.; Paranitharan, P.
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.
Ricochet of AK bullets (7.62 MM X 39 MM) on glazed ceramic tiles: An empirical study in support of shooting incident reconstructions
(Forensic Science International, 2022) Nishshanka, B.; Shepherd, C.; Punyasena, M.
Indoor environments provide numerous hard surfaces and nearby objects which facilitate the shots fired to ricochet off and hit victims. Out of many surface types, ceramic tile surfaces are considered to be one of the most commonly available and encountered surface type in indoor shootings. However, no studies had at tempted to understand the ricochet behaviour and surface evidence of ceramic tiles with any bullet type. This study explores the ricochet behaviour of one of the most commonly reported bullet type in recent shooting incidents; AK bullets (7.62 mm × 39 mm/ M43) on two glazed ceramic tile samples used for indoor walls and flooring. The study’s results present the critical angles of glazed ceramic floor and wall tile samples along with a few significant and currently not reported ricochet-surface mark characteristics with greater forensic significance for use in AK gun-related ricochet investigations. This study further emphasises the need for case-by-case empirical approaches to understanding the ricochet behaviour of different bullet- target combinations during ricochet investigations. The study also opens up a new research area to explore whether the observed results are common to steel core AK bullets or common to other ammunition types and tile surfaces with different compositions.