Unregulated 3D-printed firearms, known as 'ghost guns,' are experiencing a surge in use, leaving law enforcement agencies struggling to enforce existing firearm regulations.

In a rapidly evolving technological landscape, concerns about the proliferation of 3D-printed firearms have become a pressing issue. These weapons, often referred to as "ghost guns" due to their difficulty to trace, have been involved in several high-profile incidents and arrests around the world.

On December 4, 2024, the shooting of UnitedHealthcare CEO Brian Thompson was carried out using a 3D-printed gun, highlighting the potential danger these weapons pose. The U.S., in particular, has seen a significant number of 3D-printed gun-related arrests, accounting for 36% of total global arrests in 2023.

The use of 3D-printed firearms is a contentious issue in the U.S., where producing or owning homemade firearms for personal use is allowed. However, the type of weapon matters, with automatic weapons heavily regulated by federal law. The production or ownership of a 3D-printed conversion device that converts semi-automatic firearms into fully automatic machine guns can lead to severe penalties, including a maximum of 10 years in federal prison and a $250,000 fine.

In Europe, the European Union broadly prohibits the making or owning of homemade firearms, including 3D-printed ones. However, laws and penalties vary, with some nations criminalizing even the possession of digital files or blueprints related to 3D-printing guns. For instance, the U.K. government updated its laws in November 2022 to specifically ban possessing, buying, or producing parts for 3D-printed guns. Parliament is currently considering two bills proposing a ban on possessing blueprints for 3D-printed guns.

In contrast, Australia has declared that homemade "ghost guns" are no longer an "emerging" threat but a present danger, with police seeing a rapid increase in seizures nationwide. Making a 3D-printed firearm is illegal, and in some states, possessing a digital blueprint to create one is also an offense.

The rise in 3D-printed gun-related arrests is a global phenomenon. In North America, there were 166 cases from 2013 to June 2023. In the U.S., arrests linked to 3D-printed guns are on the rise, with 108 arrests recorded in the first half of 2023, compared to 66 arrests in all of 2022.

The number of seized 3D-printed guns in New York state alone surged dramatically, from 100 in 2019 to 637 in 2022. This trend is also visible in other regions, such as Australia, where 19,273 suspected ghost guns were traced in 2021, a significant increase from 8,504 in 2020.

Concerns about the use of 3D-printed firearms by extremists, terrorists, or paramilitary groups have also been raised. Between 2019 and mid-2022, there were at least nine documented cases in Europe and Australia of such groups either producing or attempting to produce firearms using 3D-printing technology.

In response to these concerns, various countries have taken steps to regulate 3D-printed firearms. In the U.S., for instance, 15 states had established regulations on ghost guns by November 2024, with exact requirements varying. In Canada, ghost guns were effectively banned in 2023, making it illegal to possess or manufacture them without a license from the government.

The First Amendment in the U.S. protects freedom of expression, which includes sharing digital files that could contain firearm designs. This presents a challenge in regulating the dissemination of information related to 3D-printed firearms.

As the use of 3D-printed firearms continues to grow, it is clear that a global dialogue and coordinated action are necessary to address this complex and evolving issue.