US SB1374

Prohibits the import, sale, manufacture, transfer, receipt, or possession of machinegun conversion devices, including bump stocks and similar devices that increase a semiautomatic firearm's rate of fire to approximate a machinegun, effective 120 days after enactment

Bans devices or parts designed to eliminate the need for a separate trigger movement for each shot fired, as well as semiautomatic firearms that have been modified to materially increase their rate of fire

Requires owners of previously modified semiautomatic firearms to register them under the National Firearms Act (Section 5841 of the Internal Revenue Code) within 120 days of enactment

Exempts federal, state, tribal, and local government agencies from the prohibition

Adds modified semiautomatic firearms to the National Firearms Act's definition of regulated firearms and makes violations subject to existing penalties under 18 U.S.C. 924(a)(2)