People who know me generally know that I own a 3D printer, which I use primarily for producing earrings that I have designed. Many of them are sold to benefit the Kendal Residents Association at the annual holiday sale.

Because of my 3D printer, people often ask me about the threat of 3D-printed guns. I tell them that a 3D printed gun, using the technology available to hobbyists, would be both many times as expensive as a gun from any other source and also totally unreliable.

There is indeed a problem that relates 3D printing and guns, but it is not primarily due to the actual production of 3D-printed guns.

The problem is primarily tracking guns and regulating gun sales. Every gun is required by law to be uniquely identified by a serial number engraved on the body of the gun. The serial number is supposed to be recorded by the seller whenever the gun changes ownership, and the tracking system (which is maintained by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives) is often used by police departments to help solve crimes in cases where the weapon has been recovered.

This is where 3D printing comes in. For some guns, it may be possible to 3D print a replacement for the part (generally the “lower receiver” component of a gun) where the serial number would normally be found. A replacement for this part can be 3D-printed without significantly compromising the reliability of the rest of the gun. The result is an untraceable weapon, partly 3D-printed, known as a “ghost gun”. (Guns that are completely 3D-printed are also called “ghost guns”.)

A March 2025 Supreme Court ruling makes it clear that ghost guns fall under the same rules that apply to other guns. The state of New York has begun cracking down on 3D-printed guns and gun components. Those who make 3D-printed components of guns almost always download online files that contain instructions (“digital models”) that tell their 3D printer how to make the parts. New York authorities have been able to get many of the online sites from which 3D models can be downloaded to delete their gun-related digital models.

But some right-wing libertarian groups are arguing that restrictions on ghost guns abridge their rights under the 2nd Amendment. They are openly sharing downloadable digital models on their websites.

New York City has been focusing on ghost guns and, while some progress has been made, there continue to be problems. In particular, it is not illegal to download the “lower receiver” digital models and print them, and it is not illegal to order the rest of the gun as a kit. Until those components have been assembled into a gun, nothing illegal has occurred. That creates a huge enforcement problem for police efforts to rein in ghost gun production. Bills to tighten up the laws are currently under consideration in Albany. A good summary of the current situation in New York City is here: https://www.amny.com/news/nypd-manhattan-da-ghost-gun-manufacturers/

For those of us with 3D printers (I know of two other KCC residents that have them), the questions about 3D-printed guns will surely continue.