1. Short title This Act may be cited as the Undetectable Firearms Modernization Act . 2. Modernization of the prohibition on undetectable firearms Section 922(p) of title 18, United States Code, is amended— (1) in paragraph (1)— (A) 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 Exemplar and inserting all parts other than major components, does not contain detectable material ; and (B) in subparagraph (B), by striking when subjected to inspection by the types of x-ray machines commonly used at airports, does not generate and inserting the following: if subjected to inspection by the types of detection devices commonly used at airports for security screening, would not generate ; (2) in paragraph (2)— (A) by striking subparagraph (B) and inserting the following: (B) the term major component , with respect to a firearm— (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 ; and (B) by striking subparagraph (C) and the proviso that follows and inserting the following: (C) 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. ; (3) in paragraph (3)— (A) in the first sentence, by inserting after of a firearm the following: , including a prototype, ; and (B) by striking the second sentence; and (4) in paragraph (5), by striking shall not apply to any firearm which and all that follows and inserting the following: shall not apply to— (A) any firearm received by, in the possession of, or under the control of the United States; or (B) 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. .