3D Printed Firearms Evidence

This presentation introduces the world of 3D printing and its growing role in the manufacture of privately made firearms, often referred to as “ghost guns.” Beginning with a straightforward explanation of how 3D printing works—layer by layer using a digital file and a simple desktop printer—we’ll explore how these devices can produce functional firearm components that are difficult to trace through traditional serial numbers or records. The main focus will be on the physical evidence left behind by the printing process itself: nozzle marks, layer lines, and surface patterns that can act like a printer’s unique signature.

Through controlled tests and image analysis, we’ll examine how consistent these features are across multiple prints and how they can help link a printed part back to a specific printer or setup. The talk will also look at practical investigative techniques, including high-resolution imaging and 3D surface comparison, that can help document and compare printed evidence. By the end, attendees will understand what types of markings are most promising for forensic identification, the limitations of current methods, and how to incorporate 3D-printed evidence into investigative and courtroom workflows with confidence and scientific rigor.