As most are aware, the issue of 3D printed guns comes up from time to time, usually in a negative light. Despite the controversy, scientists and enthusiasts have still provided useful designs and concepts that have taken 3D printed guns a long ways from from the first model in 2013. With an expanded 3D printing industry, some went the extra mile to contemplate how this could affect criminal investigations in the future. In 2017, a chemistry professor at the University of Mississippi, along with a graduate student began studying the physical evidence left behind from 3D printed guns. Since then, they have amassed a reference library containing more than 50 types of polymers that can be used in forensic investigations.
Ole Miss News reported on the University of Mississippi’s research team’s study, conducted by Professor James Cizdziel, Oscar Black, Robert Cody and David Edwards. The following is an excerpt from the study and summarizes Phase 2, following the destruction of their Phase 1 test gun after one shot.
In phase 2, we repeated the study using a 3D-printed 0.22 cal-iber ﬁrearm generated from ‘‘Washbear” blueprint ﬁles obtainedonline and printed using an Ultimaker 2+printer with accompany-ing CURA software. Firearm components were printed in PLA poly-mer, except the cylinders, which were interchangeable andconsisted of four separate polymers: ABS, PLA, PETG, and CPE. Forvisual simplicity, the four polymers obtained consisted of differentcolors, with white, orange, green, and blue corresponding to ABS,PLA, PETG, and CPE respectively. The ﬁring pin was machined froma 1/8″ steel drill bit blank using a dremel tool. Polymers wereobtained from commercial providers: Ultimaker and MatterHackers.In both phases of the study GSR was collected from a cottonshirt situated ~0.3 m from the gun using a standard carbon-adhesive GSR stub (Ted Pella Inc.12.7 mm SEM pin stub). Spent car-tridges, bullets and GSR stubs were wrapped in aluminum foil andshipped to JEOL USA, Inc. for DART-MS analysis.