H.R. 4221

119th CONGRESS 1st Session

To modernize the Undetectable Firearms Act of 1988.

IN THE HOUSE OF REPRESENTATIVES · June 27, 2025 · Sponsor: Ms. Dean of Pennsylvania · Committee: Committee on the Judiciary

Table of contents

• H.R. 4221
  • SEC. 1. Short title
  • SEC. 2. Modernization of the prohibition on undetectable firearms

SEC. 1. Short title

• This Act may be cited as the Undetectable Firearms Modernization Act.

SEC. 2. Modernization of the prohibition on undetectable firearms

• Section 922(p) of title 18, United States Code, is amended—
  • in paragraph (1)—
    • in subparagraph (A), by striking grips, stocks, and magazines, is not as detectable as the Security Exemplar, by walk-through metal detectors calibrated and operated to detect the Security Exemplarand inserting all parts other than major components, does not contain detectable material; and
    • in subparagraph (B), by striking when subjected to inspection by the types of x-ray machines commonly used at airports, does not generateand inserting the following: ;
  • in paragraph (2)—
    • the term , with respect to a firearm— major component
      • (i) means the slide or cylinder, or the frame or receiver of the firearm; and
      • (ii) in the case of a rifle or shotgun, includes the barrel of the firearm; and
    • by striking subparagraph (B) and inserting the following:
      • the term detectable material means material that produces a magnetic field that is equivalent in strength to the magnetic field produced by 3.7 ounces of 17–4 PH stainless steel.
    • by striking subparagraph (C) and the proviso that follows and inserting the following:
  • in paragraph (3)—
    • in the first sentence, by inserting after the following: ; and
    • by striking the second sentence; and
  • in paragraph (5), by striking and all that follows and inserting the following:
    • shall not apply to—
      • any firearm received by, in the possession of, or under the control of the United States; or
      • the manufacture, importation, possession, transfer, receipt, shipment, or delivery of a firearm by a licensed manufacturer or licensed importer pursuant to an existing contract with the United States.