Last reviewed October 31, 2026
Undetectable Firearms Act: Where It Stands in 2026
The Undetectable Firearms Act (UFA), codified at 18 U.S.C. 922(p), makes it a federal crime to manufacture, import, sell, ship, deliver, possess, transfer or receive a firearm that is not as detectable by a walk-through metal detector as a security exemplar containing 3.7 ounces of steel. It also covers firearms whose major components would not generate an accurate image in standard airport X-ray machines. President Reagan signed it on November 10, 1988, with backing from the NRA after the law was narrowed to target truly undetectable guns rather than polymer-framed pistols like the Glock.
The UFA has always carried a sunset date, and Congress has renewed it each time: for five years in 1998, ten years in 2003, ten years in December 2013, and through short-term extensions in late 2023 and early 2024. The current extension came in the FY2024 spending package (Pub. L. 118-42), signed March 9, 2024, which runs the law to March 8, 2031. Efforts to make it permanent, such as the Reed-Grassley bill S. 3677 in 2024, did not pass.
The UFA has become central to the debate over 3D-printed and home-built firearms. Gun-control groups cite it when pushing new state laws, while gun-rights advocates point out that the UFA already applies to every firearm, including home-built ones, so new restrictions on lawful home building are not needed to keep undetectable guns illegal.
Key Facts
- Statute: 18 U.S.C. 922(p); originally Pub. L. 100-649, signed November 10, 1988.
- Standard: Must be detectable as a 3.7-ounce steel security exemplar; major components must produce an accurate X-ray image.
- Renewals: 1998 (5 years), 2003 (10 years), December 2013 (10 years), short-term extensions in November 2023 (Pub. L. 118-22) and early 2024.
- March 9, 2024: Pub. L. 118-42 extends the UFA to March 8, 2031.
- As of October 2026: No permanent reauthorization has been enacted.
What Gun Owners Should Know
- The UFA applies to every firearm, including any you build for personal use where home building is legal. A firearm must contain enough metal to meet the federal standard.
- Removing or never installing a required metal component can turn a lawful firearm into a federal felony.
- Several states have their own undetectable-firearm laws, some broader than federal law. Check state law.
- Watch for the 2031 sunset; Congress will debate renewal and possible expansion again.
- Related pages: 3D Printed Guns, Ghost Guns and 80% Firearm Kits. Questions can go to Ask Gun Questions.com.
Sources
- 18 U.S.C. 922(p) (Cornell LII)
- Sen. Reed: Reed, Grassley Lead Effort to Renew the Undetectable Firearms Act (Feb. 19, 2024)
- The Trace: Undetectable Firearms Act Extended to 2031 (March 2024)
Background and Resources
