H.R. 4221 · 119th Congress · House

Undetectable Firearms Modernization Act

Active· Introduced in House
Introduced
Jun 27, 25
Passed House
Pending
Passed Senate
Pending
Sent to President
Pending
Signed into Law
Pending

Executive 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.

Action Timeline

2
  1. JUN 27, 2025House floor actions

    Referred to the House Committee on the Judiciary.

  2. JUN 27, 2025Library of Congress

    Introduced in House

Committees

1

Judiciary Committee

hsju00

Referred: Jun 27, 2025

Active