H.R. 4221 Introduced Crime and Law Enforcement

Undetectable Firearms Modernization Act

To modernize the Undetectable Firearms Act of 1988.

  1. Introduced
  2. Committee
  3. Passed House
  4. Passed Senate
  5. To President
  6. Became law
Sponsor Rep. Dean, Madeleine [D-PA-4] Introduced June 27, 2025 Cosponsors 0 Latest action June 27, 2025

Summary

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.

Summary by the Congressional Research Service, Library of Congress.

Congress.gov

Actions

  1. Jun 27, 2025 Referred to the House Committee on the Judiciary.
  2. Jun 27, 2025 Introduced in House

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