On December 26, 2018, the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) published in the Federal Register a final rule [Docket No. 2018R-22F; AG Order No. 4367-2018] that amends the ATF regulations to clarify that bump-stock-type devices—meaning “bump fire” stocks, slide-fire devices, and devices with certain similar characteristics—are “machineguns” as defined by the National Firearms Act of 1934 and the Gun Control Act of 1968 because such devices allow a shooter of a semiautomatic firearm to initiate a continuous firing cycle with a single pull of the trigger. Specifically, these devices convert an otherwise semiautomatic firearm into a machinegun by functioning as a self-acting or self-regulating mechanism that harnesses the recoil energy of the semiautomatic firearm in a manner that allows the trigger to reset and continue firing without additional physical manipulation of the trigger by the shooter. Hence, a semiautomatic firearm to which a bump-stock-type device is attached is able to produce automatic fire with a single pull of the trigger. With limited exceptions, the Gun Control Act, as amended, makes it unlawful for any person to transfer or possess a machinegun unless it was lawfully possessed prior to the effective date of the statute. The bump-stock-type devices covered by this final rule were not in existence prior to the effective date of the statute, and therefore will be prohibited when this rule becomes effective. Consequently, under the final rule, current possessors of these devices will be required to destroy the devices or abandon them at an ATF office prior to the effective date of the rule.

Machineguns, submachineguns, machine pistols, and fully automatic rifles fall within Category I(b) of the U.S. Munitions Import List when those defense articles are permanently imported. See 27 CFR 447.11, 447.21. The final rule makes it clear that bump-stock-type devices are covered. The revised section includes the following definition:

Machinegun. A “machinegun”, “machine pistol”, “submachinegun”, or “automatic rifle” is a firearm which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts designed and intended, for use in converting a weapon into a machinegun, and any combination of parts from which a machinegun can be assembled if such parts are in the possession or under the control of a person. For purposes of this definition, the term “automatically” as it modifies “shoots, is designed to shoot, or can be readily restored to shoot,” means functioning as the result of a self-acting or self-regulating mechanism that allows the firing of multiple rounds through a single function of the trigger; and “single function of the trigger” means a single pull of the trigger and analogous motions. The term “machinegun” includes a bump-stock-type device, i.e., a device that allows a semi-automatic firearm to shoot more than one shot with a single pull of the trigger by harnessing the recoil energy of the semiautomatic firearm to which it is affixed so that the trigger resets and continues firing without additional physical manipulation of the trigger by the shooter.

The rule is effective March 26, 2019.