; and (B) by adding at the end the following: (38) The term bump stock has the meaning given such term in section 5845(n) of the National Firearms Act ( 26 U.S.C. 5845(n) ). . (2) Section 922 of title 18, United States Code, is amended— (A) in each of subsections (a)(4) and (b)(4), by inserting bump stock, before machinegun ; and (B) in subsection (o)— (i) in paragraph (1), by inserting or bump stock before the period; and (ii) in paragraph (2)— (I) in subparagraph (A), by striking or at the end; (II) in subparagraph (B), by striking the period and inserting ; or ; and (III) by adding at the end the following: (C) the otherwise lawful possession of a bump stock that, on or before the date that is 1 year after the date of the enactment of this subparagraph, is registered to the possessor in accordance with section 5841 of the Internal Revenue Code of 1986. . (c) Effective date (1) In general The amendments made by this section shall take effect on the date of the enactment of this Act. (2) Application to possession on date of enactment Notwithstanding paragraph (1), any person on the date of the enactment of this Act possessing a bump stock as defined in section 5845(n) of the Internal Revenue Code of 1986 (as amended by this Act) shall, not later than the date that is 1 year after the date of the enactment of this Act, register such bump stock in accordance with section 5841 of the Internal Revenue Code of 1986 and include with such registration the information required under section 5841(a) of such Code. Such registration shall become a part of the National Firearms Registration and Transfer Record required to be maintained by such section. The prohibition on possession of an unregistered firearm under section 5861 of such Code shall not apply to a bump stock described in this Act on any date that is 1 year or less after the enactment of this Act.