Centre for Forensic Science, University of Technology Sydney, Broadway, NSW, 2007, Australia.
Centre for Forensic Science, University of Technology Sydney, Broadway, NSW, 2007, Australia.
Forensic Sci Int. 2021 Mar;320:110685. doi: 10.1016/j.forsciint.2021.110685. Epub 2021 Jan 11.
In recent years, sawn-off shotguns have been regularly encountered in firearm-related incidents. Shotgun represents a community threat due to their ability to be shortened in order to improve their concealability. In practice, forensic scientists and investigators may be asked to determine if a shotgun used in a particular event might have been shortened based on the pellet distribution. To investigate the effect of altering the barrel length on pellet distribution, five 12-gauge shotguns were progressively shortened. Each shotgun was assessed at six barrel lengths and a single discharge of No. 4 shot shotshell ammunition was fired at a fixed fabric target. The shotguns were positioned at six different distances from target and experiments conducted in triplicate. The fabric targets containing pellet pattern underwent data analysis to calculate the pellet distribution area. At short distances from target (≤ 1.0 m), the pellet penetration was observed as a single entry point as the pellets did not have a sufficient flight time to spread from each other. For distances of 2.5 m, 5 m and 10 m, pellet penetration patterns were observed and a quantitative analysis was performed on the samples containing pellet distribution patterns. At each of these distances, it was detected that there was a noticeable increase in pellet distribution area between the unaltered shotgun and altered barrel lengths for all shotguns. The distance from the target as well as the presence of a choke in the shotgun's barrel was found to have a greater impact on the pellet distribution than the barrel length.
近年来，短管霰弹枪在与枪支有关的事件中经常被发现。霰弹枪因其能够缩短以提高隐蔽性而对社区构成威胁。在实践中，法医学家和调查人员可能会被要求根据弹丸分布来确定在特定事件中使用的霰弹枪是否被缩短过。为了研究改变枪管长度对弹丸分布的影响，对五支 12 号口径的霰弹枪进行了逐步缩短。每支霰弹枪在六个枪管长度上进行了评估，并在固定的织物目标上单次发射了 4 号霰弹弹药。霰弹枪以六个不同的距离定位在目标上，每个距离重复进行三次实验。对包含弹丸图案的织物靶进行数据分析，以计算弹丸分布区域。在靠近目标的短距离（≤1.0m），弹丸穿透被观察为单个进入点，因为弹丸没有足够的飞行时间相互扩散。对于 2.5m、5m 和 10m 的距离，观察到了弹丸穿透模式，并对包含弹丸分布模式的样本进行了定量分析。在这些距离中的每一个，都发现所有霰弹枪的未改变的霰弹枪和改变的枪管长度之间的弹丸分布区域都有明显的增加。研究发现，距离目标的远近以及霰弹枪枪管中是否有阻气阀对弹丸分布的影响比枪管长度更大。
