H.R. 4221 · Where this bill is now
In committee
Introduced in the House, sent to the Committee on the Judiciary, Jun 27, 2025
What this bill does
In plain words · AI-written from the official summaryStrengthens rules for detectable firearm materials
Current federal law requires firearms to contain enough metal so they can be detected by security metal detectors, but only after removing grips, stocks, and magazines. This bill tightens that requirement by saying firearms must remain detectable even after removing almost all removable parts. It also updates which firearms are exempt from these rules, including those made under contract with the U.S. government.
How it affects you
This primarily affects firearm manufacturers, who must ensure their products meet stricter detectability standards. For the average person, it means increased consistency in security screening at airports and other facilities that use metal detectors to screen for weapons.
Read the official summary (Introduced in House, Jun 27, 2025)
Undetectable Firearms Modernization Act
This bill strengthens the detectability standard for firearms under federal firearms laws.
Current law requires firearms to be detectable by walk-through metal detectors after the removal of grips, stocks, and magazines. Specifically, firearms must be as detectable as a security exemplar (i.e., a piece of stainless steel that is 3.7 ounces and in a shape resembling a handgun). There are exceptions, including for firearms manufactured for or sold to U.S. military or intelligence agencies.
This bill requires firearms to contain detectable material after the removal of all parts other than major components. It defines detectable material as material that produces a magnetic field equivalent to that produced by 3.7 ounces of stainless steel. The bill also revises and broadens the exceptions to include firearms (1) received by, in the possession of, or under the control of the United States; or (2) produced pursuant to a contract with the United States.
Written by AI (Claude) using only the official summary by the Congressional Research Service, the Library of Congress’s nonpartisan research staff. It can miss nuance, so check the official summary and the bill text for details.
1st SessionH. R. 4221
A BILL
Undetectable Firearms Modernization Act
Sponsor: Rep. Madeleine Dean (D-PA-4) · Introduced Jun 27, 2025 · Crime and Law Enforcement · 1 version of the text
Sources: Congress.gov actions and votes · bill text from GovInfo · latest official action Jun 27, 2025: “Referred to the House Committee on the Judiciary.”