; (3) in paragraph (2)— (A) by amending subparagraph (A) to read as follows: (A) the term undetectable firearm means a firearm, as defined in section 921(a)(3)(A), of which no major component is wholly made of detectable material; ; (B) 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 (C) by striking subparagraph (C) and all that follows through the end of the undesignated matter following subparagraph (C) and inserting the following: (C) the term detectable material means any material that creates a magnetic field equivalent to or more than 3.7 ounces of 17–4 pH stainless steel. ; (4) in paragraph (3)— (A) in the first sentence, by inserting , including a prototype, after of a firearm ; and (B) by striking the second sentence; and (5) 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 a contract with the United States. .