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BackgroundHandguns and rifles are often involved in violent deaths such as homicide and suicide. Consequently, forensic investigations are important to clarify the nature of ballistic trauma.MethodsThis study investigated the differences in entrance and exit wound morphology with Bos taurus (bovine) scapulae that have two cortical layers surrounding a central cancellous bone section which are comparable with human flat bones, with a series of experiments using six different calibres (0.22 Long Rifle, 9×19 mm North Atlantic Treaty Organization, 0.40 Smith & Wesson, 0.45 Automatic Colt Pistol, 5.56×45 mm and 7.62×51 mm). B. taurus (bovine) scapulae were used for closed range 30 cm simulated executions.ResultsThe ballistic experiments presented similarities in entrance wound morphology and exit wound bevelling with that of recognised forensic cases. As muzzle velocity increased, bevelling increased. Circumferential delamination is clearly visible with full metal jacket rounds, yielding similar bone damage morphology as human crania.ConclusionBovine scapulae seem appropriate for ballistic simulations of flat bone injuries on the macroscopic level, if the correct portion of the scapulae is deployed. More research is needed to further substantiate these interpretations.

A systematic review of the literature was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method to investigate the frequency of military thoracic gunshot wounds (GSWs) and deaths in combat theatres since World War Two (WW2). An electronic database search of World of Science, Scopus, Science Direct, PubMed and Microsoft Academic was conducted using the keywords ‘combat, casualties, thorax, gunshot, and military’ to identify peer-reviewed journals and conference papers on the topic. Twenty-three sources relevant to this review were identified and covered multiple theatres of operation. While there is a downward trend in the frequency of thoracic GSWs and fatalities likely due to the improvement of body armour, the improvement in medical treatment and increased frequency of improvised explosive devices (IEDs), the review shows that the advancement has not removed the likelihood of thoracic GSWs, which still accounted for approximately 15% of all thoracic injuries in the most recent combat theatres. The systematic review identifies that GSWs of the thorax continue to be a risk in military theatres and therefore, medical personnel should be aware of the frequency and severity of thoracic GSWs and should be prepared to treat these life-threatening injuries, as timely intervention is essential.

Mass loss was the only quantifiable measure of changes in the blocks with time, but did not correlate with any changes in DoP. This may provide reassurance when undertaking such testing that an inadvertent delay will not significantly alter the penetration properties of the mould. Future research is recommended to determine any potential effect on the mechanical properties of gelatin at higher velocity impacts and whether the calibration corresponds to an adequate simulation under such conditions.

IntroductionA review of ballistic gelatin calibration standards has highlighted that data used from studies with different calibrations methods may not be able to be compared. Calibration of ballistic gelatin did not occur until the mid-1980s when Fackler recognised the deficiencies of uncalibrated gelatin. He determined that the calibration standard should be 85±5 mm of ball bearing penetration for a 180 m/s impact velocity. This study looks to improve on and optimise current ballistic gelatin calibration standardsMethodsNine 0.177 cal (4.5 mm) spheres were fired using a Daisy Powerline air rifle at velocities between 134 m/s and 224 m/s at 25 gelatin blocks (n=225). Velocities were measured using an Oehler Model 36 Chronograph with three Model 57 screens. Depth of penetration (DoP) was measured from the entry surface to the back end of the sphere via a Mitutoyo Absolute vernier calliper.ResultsThe R-squared regression model showed that all batches had a close fit to the regression line. Using the R-squared regression model, the equation y=0.584x – 20.02 (where x is the velocity) returned a DoP of 84.918 mm for a 180 m/s impact and therefore needed minimal adjustment to align with Fackler’s 85 mm DoP. The equation can be adjusted to y=0.584x – 20.12 to return a DoP of 85 mm for 180 m/s.ConclusionsWe propose that the calibration standard of ballistic gelatin with 4.5 mm spheres is DoP=0.584x – 20.12 where DoP is the depth of penetration (mm) and x is the impact velocity (m/s), The measured DoP should be within 5% of the calculated DoP.

BackgroundThe prevalence of civilian 0.223 ammunition is widespread. Due to low costs and the same dimensions as a 5.56×45 mm North Atlantic Treaty Organization, this round is exceptionally popular. However, recent mass shootings have employed soft point (SP) expanding ammunition to cause grievous wounds compared with military full metal jacket (FMJ) rounds that do not rapidly expand on impact.MethodsThe aim of this given study is to compare FMJ and SP rounds to determine if there are diagnostic differences between the bullet types in the wounds inflicted to flat bones. Bos taurus scapulae were used for 25 m simulated cranial gunshot injuries. Scanning electron microscopy was employed to assess the difference in wound morphology and elemental analysis between SP and FMJ rounds.ResultsEntrance and exit wound morphology change significantly between the two different types of ammunition as seen with circumferential delamination which is indicative of FMJ rounds and is not seen with the softer SP hunting rounds. Lead staining of the entrance wound is visible on only the SP rounds.ConclusionGunshot flat bone wound morphology is distinctively different between SP and FMJ rounds. Circumferential delamination is only seen with FMJ due to the hardness of the round. Lead staining is only seen with SP rounds due to bullet composition.

This study provides new insights into the role of rib impact in thoracic gunshot injuries, and indicates that the effects are ammunition dependent. Unlike the 5.56×45 mm rounds, rib impact with the 7.62×51 mm rounds increases the risk of severe wounding.

While tissue simulants are considered best practice for ballistic evaluations, there is an ongoing debate about the use of tissue simulant and their relevance and there are calls to improve models by making them more anatomically relevant by the introduction of bony structures and organs. Therefore; the aim of this study was to try and determine if sponges and/or ballistic gelatin may be a suitable proxy to porcine lungs using 5.56x45mm (MK262-MOD1). Four sample groups consisting of 10% ballistic gelatin blocks, lungs embedded in gelatin, kitchen sponges and car sponge in gelatin were evaluated. Analysis included determining the onset of yaw, time from impact to the onset of yaw, temporary and permanent cavity characteristics and energy deposition. The results indicated that the kitchen sponge and car sponge may be a suitable proxy to porcine lungs, however there were significant differences between the lung model and plain gelatin blocks and additional work should be carried out to investigate the suitability of sponges as a proxy to porcine lungs further.