; (D) the combination of parts is designed to be assembled into a firearm that operates as a firearm included on the list of prohibited gas-operated semi-automatic firearms described in section 935(a); (E) the combination of parts functions to produce a gas-operated semi-automatic cycling action that was not lawfully manufactured as part of an approved firearm design described in section 935(c); (F) the manual, power-driven, or electronic device is primarily designed, or redesigned, so that if 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; (G) the device, part, or combination of parts is designed and functions to materially increase the rate of fire of the 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 (H) the semi-automatic firearm 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) Paragraph (1) shall not apply to— (A) the importation or manufacture by or for, sale or 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; (B) the importation or manufacture for, sale or transfer to, or possession by, a licensee under title I of the Atomic Energy Act of 1954 ( 42 U.S.C. 2011 et seq. ) for purposes of establishing and maintaining an on-site physical security protection system and security organization required by Federal law, or the transfer to, or possession by, a contractor of such a licensee on-site for such purposes or off-site for purposes of licensee-authorized training or transportation of nuclear materials