; and (9) a bump stock. ; and (2) by adding at the end the following new subsections: (n) Bump stock The term bump stock means any of the following: (1) Any manual, power-driven, or electronic device that is designed such that when the device is attached to a semiautomatic weapon, the device eliminates the need for the operator of a semiautomatic weapon to make a separate movement for each individual function of the trigger and— (A) materially increases the rate of fire of the semiautomatic weapon, or (B) approximates the action or rate of fire of a machinegun. (2) Any part or combination of parts that is designed and functions to eliminate the need for the operator of a semiautomatic weapon to make a separate movement for each individual function of the trigger and— (A) materially increases the rate of fire of a semiautomatic weapon, or (B) approximates the action or rate of fire of a machinegun. (3) Any semiautomatic weapon that has been modified in any way that eliminates the need for the operator of the semiautomatic weapon to make a separate movement for each individual function of the trigger and— (A) materially increases the rate of fire of the semiautomatic weapon, or (B) approximates the action or rate of fire of a machinegun. (o) Semiautomatic weapon The term semiautomatic weapon means any repeating weapon that— (1) utilizes a portion of the energy of a firing cartridge or shell to extract the fired cartridge case or shell casing and chamber the next round, and (2) requires a separate function of the trigger to fire each cartridge or shell. . (b) Amendments to title 18 , United States Code (1) Section 921(a) of title 18, United States Code, is amended— (A) in paragraph (3), by striking muffler or firearm silencer and inserting muffler, firearm silencer, or bump stock