; and single function of the trigger means a single pull of the trigger and analogous motions. ; and (2) by adding at the end the following: (aa) (1) Acceleration devices It shall be unlawful for any person to manufacture, import, sell, ship, deliver, possess, transfer, or receive, in or affecting interstate or foreign commerce, any part, combination of parts, component, device, attachment, or accessory that is designed and functions to accelerate the rate of fire of a semiautomatic firearm but not convert the semiautomatic firearm into a machinegun. (2) Exceptions Paragraph (1) of this subsection shall not apply to— (A) the otherwise lawful possession of a device before the date that is 90 days after this subsection takes effect, provided that the device is destroyed or disposed of within that 90-day period; (B) the importation, manufacture, possession, or receipt of such devices by or for, or shipment, sale, or transfer of such devices for or to, the United States, a department or agency of the United States, a State, or a department, agency, or political subdivision of a State, for the purposes of testing or experimentation authorized by the Attorney General; or (C) a part that designed and functions to replace a part of a firearm that has been damaged or that has reduced functionality due to normal wear and tear, regardless of whether that part improves the performance or functionality of the firearm beyond its original performance and functionality. . (b) Penalties Section 924(a)(2) of such title is amended by striking or (o) and inserting (o), or (aa) .