The Relevance of Current Forensic Firearms Examination Techniques When Applied to 3D Printed Firearms

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Presenter(s)

Zara Wenzinger

Abstract or Description

As 3D printing technology progresses and becomes more accessible to consumers, the rapidly emerging field of 3D printed firearms poses a significant threat to public safety. This research investigates how the Trace Evidence and Firearms & Toolmark sections of forensic science can be applied to 3D printed firearms. Is gunshot residue (GSR) depositing the same way and is thermoplastic polymer residue from the 3D printed firearm present? And are unique striae being deposited on bullets and cartridges cases fired by 3D printed firearms that could be used for identification purposes? A 3D printed model, the Liberator, was printed on a cheap commercial printer out of polylactic acid (PLA). After printing and handling the barrels, GSR stubs after were taken and analyzed using SEM-EDS to ensure no thermoplastic polymer particles were present in trace amounts and that lead, antimony, and barium were not deposited during the printing process. After firing, GSR stubs were collected from the cartridge case, the bullet, and the barrel. These GSR stubs were analyzed using SEM-EDS for standard GSR (lead, antimony, and barium) and identified GSR particles were observed manually to determine if PLA residue could be identified. All three samples had more than 100 three-component particles, the threshold for the program, but more analysis must be done to identify any presence of polylactic acid. The bullet and cartridge case were viewed using a Leeds LCF Firearms Comparison Microscope with Olympus SZX12 to identify any class or individual characteristics present. No rifling was present on the bullet and the cartridge case did not have a firing pin impression meaning both would be classified as unsuitable for identification. In conclusion, this novel research aims to answer questions regarding the analysis of forensic evidence obtained from 3D printed firearms before any potential widespread use.   

Mentor

Pamela Marshall