H.R. 4221 · 119th Congress
Undetectable Firearms Modernization Act
Key: what the circles and colors mean
Each circle is a bill. The ring fills as it moves through Congress:
Under the number: the Yea · Nay count of its final (or latest) recorded vote. On a member's page, the small badge is how that member voted: Y Yea / Aye, N Nay / No, P Present, – Not voting.
Gold and violet are only for Yea and Nay; they never mean a party. A member's party is the letter on their photo.
Not yet voted on. This bill is still a proposal: it hasn't reached a floor vote, and its text can change in committee or on the floor before any vote.
D
DeanSponsorNo cosponsors.
This bill strengthens the detectability standard for firearms under federal firearms laws.
What it does: CRS 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 the nonpartisan Congressional Research Service. All summary versions on Congress.gov
About this bill and sources
Official title: Undetectable Firearms Modernization Act
Latest action (Jun 27, 2025): Referred to the House Committee on the Judiciary.
Policy area: Crime and Law Enforcement · Origin: House · Introduced: Jun 27, 2025
Official page on Congress.gov · Bill text (GovInfo) · Status record (XML)
No recorded floor vote found.