Closing the Bump Stock Loophole Act of 2025

“(31) The term semiautomatic firearm means any firearm that—

“(A) upon initiating the firing sequence, fires the first chambered cartridge and uses a portion of the energy of the firing cartridge to—

“(i) extract the expended cartridge case;

“(ii) chamber the next round; and

“(iii) prepare the firing mechanism to fire again;

“(B) requires a separate pull, release, push, or initiation of the trigger to fire each cartridge; and

“(C) is not a machinegun.”

“(v)

“(1) Except as provided in paragraphs (3) and (4), on and after the date that is 120 days after the date of enactment of this subsection, it shall be unlawful for any person to import, sell, manufacture, transfer, receive, or possess, in or affecting interstate or foreign commerce—

“(A) any manual, power-driven, or electronic device primarily designed, or redesigned, so that when the device is attached to a semi-automatic firearm the device—

“(i) materially increases the rate of fire of the firearm; or

“(ii) approximates the action or rate of fire of a machinegun;

“(B) any device, part, or combination of parts, that is designed or functions to materially increase the rate of fire of a semi-automatic firearm, by eliminating the need for the operator of the firearm to make a separate movement for each individual function of the trigger; or

“(C) a semi-automatic firearm that has been modified in any way that—

“(i) materially increases the rate of fire of the firearm; or

“(ii) approximates the action or rate of fire of a machinegun.

“(2) Except as provided in paragraph (3), not later than 120 days after the date of enactment of this subsection, any person who lawfully owns or possesses a semi-automatic firearm that was modified as described in paragraph (1)(C) before such date of enactment shall register the semiautomatic firearm in accordance with section 5841 of the Internal Revenue Code of 1986.

“(3) This subsection does not apply with respect to the importation for, manufacture for, sale to, transfer to, or possession by or under the authority of, the United States or any department or agency thereof or a State or Tribe, or a department, agency, or political subdivision thereof.

“(4) Paragraph (1) shall not apply to any lawful transfer or possession of a semi-automatic firearm described in paragraph (1)(C) that—

“(A) was lawfully modified and possessed before the date of enactment of this subsection; and

“(B) is registered in accordance with paragraph (2).”