By: Colin Murphy

3D printing, a technology only a few decades old, has progressed in quality and affordability. It has moved from the realm of industrial prototype, through cutting-edge design and technology, to finally end up in the homes of hobbyists and enthusiasts. This welcome and useful process has delivered new and affordable solutions to a range of subjects and fields, and has changed the shape of manufacturing from large factories to small bespoke businesses. However, this innovation has also developed a darker side and has been adopted by those with criminal intent, including for the manufacture of firearms. While converted or backstreet guns are not a new phenomenon, the advent of 3D printing has extended the range of people able to obtain a firearm to include those with no practical skills or tools or indeed any criminal connections. In the space of little over a decade, the concept of homemade guns using 3D printing techniques has evolved from a simple yet effective one-shot pistol to a semi automatic hybrid rifle. These firearms have made their way into the hands of criminals and extremists with menacing intent. They have also featured in high-profile shootings with fatal consequences. It is important to acknowledge that this nascent method of firearm production is developing at a rapid speed. Authorities and law enforcement agencies are recognising the growing threat that these firearms pose, and are adapting their understanding, approach and expertise. In addition, legislators around the world are beginning to adapt their laws to address this emerging threat. In the EU, possession of a 3D-printed firearm is an offence, but not possession of, publicity for or distribution of digital blueprints or hard copies. IN THIS BRIEFING • Introduction • 3D printing • Craft production of privately-made firearms . • Progression of 3D printed firearms • Users of 3D printed firearms • Addressing the issue

Members' Research Service PE 775.889 – August 2025

By Everytown for Gun Safety, Everytown Research and Policy

  The shooting of UnitedHealthcare CEO Brian Thompson using a homemade firearm with a 3D-printed frame and silencer marked the first time many in the general public heard about 3D-printed guns. But this was not the first instance of criminal violence with this type of firearm, and as 3D-printing technology becomes more aordable, accessible, and advanced, it will not be the last. The proliferation of 3D-printed firearms (3DPFs) has emerged as a serious and accelerating public safety challenge. The current state of 3D-printing technology allows an individual to print all or key parts of a firearm at home. Like other kinds of ghost guns, 3DPFs lack serial numbers, so law enforcement is unable to trace them back to their owner when they are recovered in a crime. Because 3DPFs are untraceable and require no background check, they are particularly attractive to gun trackers who can print dozens of firearms and avoid raising alarms. 3DPFs have been linked to violent crimes, including everything from extremist plots to shootings involving teens. And the online community that produces and beta tests these designs includes alarming extremist elements, with many designers viewing 3D printing as a means to bypass or dismantle gun laws altogether. In the United States, as regulatory pressure in recent years has significantly reduced the availability of ghost gun “kits”—a way that online retailers routinely sold easily modified building blocks of firearms—the 3D printing of frames and accessories has accelerated among those looking to manufacture their own guns. Meanwhile, in Europe, new 3DPF designs allowing people to print functioning firearms threaten to undermine the gun safety laws that have long protected the continent from the degree of gun violence in the US. Policymakers, technology firms, and civil society must act urgently to address the dangers of 3DPFs. A multipronged strategy is essential. This includes 3D-printer manufacturers and software companies developing and implementing algorithms that detect and block the printing of firearms and accessories. In concert with the 3D-printing industry, lawmakers should take steps to regulate 3D-printing technology in a manner that makes it impossible to use a 3D printer to print a gun. Public institutions like schools, libraries, and community tech labs should implement clear policies and software restrictions to block the printing of firearm components on 3D printers. Further, social media and other online platforms should significantly improve their moderation of content that promotes or distributes 3Dprinted gun blueprints or features instructions and advice for building 3DPFs.