Justice Thomas continued in relevant part: ATF exceeded its statutory authority by issuing a Rule that classifies a bump stock as a “machinegun” under §5845(b). A semiautomatic rifle equipped with a bump stock is not a “machinegun” as defined by §5845(b) because: (1) it cannot fire more than one shot “by a single function of the trigger” and (2) even if it could, it would not do so “automatically.” ATF therefore exceeded its statutory authority by issuing a Rule that classifies bump stocks as machineguns. P.
A semiautomatic rifle equipped with a bump stock does not fire more than one shot “by a single function of the trigger.” The phrase “function of the trigger” refers to the mode of action by which the trigger activates the firing mechanism. No one disputes that a semiautomatic rifle without a bump stock is not a machinegun because a shooter must release and reset the trigger between every shot. And, any subsequent shot fired after the trigger has been released and reset is the result of a separate and distinct “function of the trigger.” Nothing changes when a semiautomatic rifle is equipped with a bump stock. Between every shot, the shooter must release pressure from the trigger and allow it to reset before reengaging the trigger for another shot. A bump stock merely reduces the amount of time that elapses between separate “functions” of the trigger. ATF argues that a shooter using a bump stock must pull the trigger only one time to initiate a bump-firing sequence of multiple shots. This initial trigger pull sets off a sequence—fire, recoil, bump, fire—that allows the weapon to continue firing without additional physical manipulation of the trigger by the shooter. This argument rests on the mistaken premise that there is a difference between the shooter flexing his finger to pull the trigger and pushing the firearm forward to bump the trigger against his stationary finger. Moreover, ATF’s position is logically inconsistent because its reasoning would also mean that a semiautomatic rifle without a bump stock is capable of firing more than one shot by a “single function of the trigger.” Yet, ATF agrees that is not the case. ATF’s argument is thus at odds with itself.
The Government’s recourse in light of this holding will be to lobby for the outlawing of bump stocks. That will be a difficult task given the NRA’s strong lobby and the unwillingness of many legislators to risk offending their constituents. Those concerns did not apply to the unelected ATF employees who sought to outlaw bump stocks through the agency’s “rule-making” powers.
