Honsberger Hanna, Rhumorbarbe Damien, Werner Denis, Riva Fabiano, Glardon Matthieu, Gallusser Alain, Delémont Olivier
Ecole des sciences criminelles, University of Lausanne, Lausanne, Switzerland.
Ecole des sciences criminelles, University of Lausanne, Lausanne, Switzerland.
Forensic Sci Int. 2018 May;286:245-251. doi: 10.1016/j.forsciint.2018.03.026. Epub 2018 Mar 20.
The Liberator is a firearm that can be manufactured from its blueprints, using a 3D-printer. This weapon made of nineteen pieces - eighteen in printed plastic and one metallic nail - raises questions such as its ability to fire a round, its wounding potential and the traces produced by its discharge. In particular, knowledge must be gained to infer that a 3D-printed handgun was used, reconstruct the shooting event involving such handgun, and gather information related to the type of 3D-printed handgun used. This study focused on the traces that could orientate forensic investigations when the use of a 3D-printed Liberator is suspected. In a first step, the Liberator was investigated to study its behaviour during the discharge and characterize traces produced by the discharge. To fulfil this goal, some Liberators were printed and assembled. Six Liberators fired a round. The discharge of the weapons was done under specific conditions allowing to collect ballistics data and traces produced by the shooting. The results showed that the barrel tended to break between the ignition of the primer and the moment the projectile exited the muzzle. The speed of the projectiles reached 140m/s when the barrel broke, while it was about 170m/s when barrel remained intact. The trajectory of the projectiles was sometimes disrupted, and the projectile tumbled on itself. It was thus very difficult to characterize the trajectory. The cavity wound caused by the fastest bullet was typical of a handgun wound firing a FMJ projectile (penetration of 21cm in ballistics soap). On the other hand, the cavity caused by the slowest bullet was more representative of a splinter wound (penetration of 14cm in ballistics soap). The study of gunshot residues collected on adhesive targets showed the presence of unburnt particles and small perforations caused by polymer pieces that concentrated around the entry holes.
“解放者”手枪是一种可利用其蓝图通过3D打印机制造出来的枪支。这种由19个部件制成的武器——18个打印塑料部件和1个金属钉子——引发了诸多问题，比如其射击能力、致伤潜力以及射击产生的痕迹。特别是，必须获取相关知识，以推断是否使用了3D打印手枪，重构涉及此类手枪的枪击事件，并收集与所使用的3D打印手枪类型相关的信息。本研究聚焦于在怀疑使用了3D打印的“解放者”手枪时，可为法医调查提供方向的痕迹。第一步，对“解放者”手枪进行研究，以了解其射击过程中的表现并确定射击产生的痕迹特征。为实现这一目标，打印并组装了一些“解放者”手枪。6支“解放者”手枪进行了射击。武器射击是在特定条件下进行的，以便收集弹道数据和射击产生的痕迹。结果表明，枪管往往在底火点火到子弹离开枪口的瞬间之间断裂。枪管断裂时子弹速度达到140米/秒，而枪管保持完整时约为170米/秒。子弹的轨迹有时会受到干扰，子弹会自行翻滚。因此，很难确定轨迹特征。速度最快的子弹造成的腔洞伤是典型的发射全金属被甲弹的手枪伤（在弹道肥皂中的穿透深度为21厘米）。另一方面，速度最慢的子弹造成的腔洞伤更具碎片伤的特征（在弹道肥皂中的穿透深度为14厘米）。对粘贴式靶标上收集的枪击残留物的研究表明，存在未燃烧颗粒以及由聚合物碎片造成的小孔，这些小孔集中在入口孔周围。
