An empirical study on the close-range post-ricochet orientation of AK bullets (7.62 mm × 39 mm).

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.

Ricochet of AK bullets (7.62 MM X 39 MM) on glazed ceramic tiles: An empirical study in support of shooting incident reconstructions.

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 attempted 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.

Ricochet of AK bullets (7,62 × 39 mm) on concrete and cement surfaces; a forensic-based study.

The ricochet behaviour of AK bullets (7,62 x 39 mm) on two different concrete samples (rough and a cement-skimmed intermediate) and one cement sample were explored in this study. The estimated critical angles for these surfaces were shown to be 10.8° and 11.1° for the rough and intermediate concrete surfaces and 13.2° for the cement surfaces. In all occasions, fragmentation of the bullets was observed upon reaching critical angles. The results from the concrete surfaces highlighted the sensitivity of AK bullet ricochet angles from concrete surfaces with a different surface roughness and composition. Almost all resulting ricochet angles for the more frangible cement surfaces were observed to be much higher than currently reported literature would suggest. Consistent bullet wipe markings were observed on most samples, acting as a strong indicator for the directionality of the projectile during ricochet. Interestingly for the cement surface, a clear relationship was reported between the angle of incidence and the depth of the crater produced. Ultimately, this study highlights the potential uncertainties and possible errors that could occur in bullet trajectory determination from ricochet marks for this bullet and target combination if theoretic interpretations alone are used. There is no substitute for bullet and surfacespecific practical trials if the most accurate shooting scene reconstructions are to be carried out.