Garland v. Cargill Revisions: 6/14/24
The Court ruled that bump stocks — accessories that allow semiautomatic rifles to fire much faster — do not legally turn those rifles into 'machineguns' under the federal definition, meaning the ATF had no authority to ban them through its own rulemaking.
The decision lifts the federal bump stock ban imposed after the 2017 Las Vegas massacre and makes clear that only Congress, not the ATF, can extend the machinegun prohibition to cover bump stocks.
How it got here: A federal district court ruled for ATF; a Fifth Circuit panel initially affirmed, but the full Fifth Circuit reversed en banc; the government asked the Supreme Court to step in and the Court agreed to hear it.
The Case in Depth
What happened
After a gunman used semiautomatic rifles fitted with bump stocks to kill 58 people and wound more than 500 at an outdoor concert in Las Vegas in 2017, the ATF reversed its decade-long position and issued a rule classifying bump stocks as illegal "machineguns." Michael Cargill, a Texas gun-store owner, surrendered his two bump stocks under protest and sued, arguing that bump stocks do not fit the statutory definition of a machinegun and that ATF had exceeded its legal authority.
The question before the Court
Does adding a bump stock to a semiautomatic rifle convert it into a federally banned "machinegun," giving the ATF authority to prohibit bump stocks under existing law?
The Court's answer
No — the Court ruled that a bump stock does not transform a semiautomatic rifle into a "machinegun" under federal law, and that the ATF therefore exceeded its authority by banning bump stocks through agency rulemaking.
The statutory definition requires a weapon that fires "automatically more than one shot...by a single function of the trigger." The Court concluded that a bump-stock-equipped rifle fails this test on two independent grounds. First, each shot still requires the trigger to be released and reset — just as with any semiautomatic rifle — so each shot is the product of a separate trigger function; the bump stock merely speeds up the cycle. Second, even setting aside the first point, the rifle does not fire multiple shots "automatically" because the shooter must continuously maintain the right amount of forward pressure on the front grip throughout firing, which is active manual input beyond simply operating the trigger once.
Curious how the Court got there? See the step-by-step legal reasoning →
Why it matters
Bump stocks can no longer be banned by federal regulators under current law — owners who surrendered theirs have no remedy, and anyone who wants a federal ban must persuade Congress to change the statute. The ruling also signals limits on how far federal agencies can stretch existing statutory definitions to address new threats without legislative action.
What changes now
The Fifth Circuit's ruling striking down ATF's bump stock ban stands, and the ban is lifted. People who surrendered bump stocks under the now-invalidated rule have no judicial remedy from this decision. Justice Alito's concurrence explicitly invites Congress to amend §5845(b) to cover bump stocks — an action several bills have proposed but none has accomplished. Until Congress acts, bump stocks remain legal under federal law.
What this does not decide
The ruling addresses only bump stocks and the §5845(b) machinegun definition. It does not decide whether other rapid-fire accessories — such as forced reset triggers, motorized trigger devices, or spring-operated bump stocks — qualify as machineguns, nor does it say whether Congress could constitutionally ban bump stocks if it chose to.
Concurrences and dissents
Concurrence — Justice Alito
Justice Alito agreed that the statutory text left no other option but stressed that the outcome was not necessarily what Congress intended. He acknowledged that the 2017 Las Vegas shooting showed bump-stock rifles can be just as lethal as traditional machineguns, and that this strengthens the case for changing the law. He concluded by pointing to Congress as the body that can and should act to close the gap.
Dissent — Justice Sotomayor
Justice Sotomayor argued that a bump-stock-equipped rifle plainly fits the ordinary meaning of 'machinegun': a single pull of the trigger — combined with the automatic recoil-harnessing action of the bump stock — produces continuous fire, just as with an M16. She criticized the majority for fixating on internal trigger mechanics while ignoring the shooter's perspective, said the decision eviscerates Congress's machinegun ban, and warned that the ruling will have deadly consequences by allowing devices that replicate machinegun firepower to remain in civilian hands.
How the Court got there
The legal reasoning, step by step
- The Court started with the statutory text of 26 U.S.C. §5845(b), which defines a 'machinegun' as a weapon capable of firing 'automatically more than one shot, without manual reloading, by a single function of the trigger.' It treated two phrases — 'single function of the trigger' and 'automatically' — as independent requirements that both must be satisfied, and analyzed the bump-stock rifle against each in turn.
- On the first requirement: A 'function of the trigger' is the mode of action by which the trigger activates the firing mechanism — for a standard curved-lever trigger, each press-and-release cycle is one function. Because a bump-stock-equipped rifle still requires the trigger to be released and reset between every shot, each shot is the result of a separate, distinct trigger function. The bump stock only compresses the time between those functions; it does not eliminate them.
- The Court rejected ATF's argument that the shooter's initial trigger pull starts an uninterrupted multi-shot sequence. ATF's own rule defined 'single function of the trigger' to include 'analogous motions' such as pushing the rifle forward — but if each forward push is an analogous trigger function, then each bump is itself a separate function, which actually refutes ATF's position. The Court also noted the logical inconsistency: ATF's reasoning would equally imply that a plain semiautomatic rifle without a bump stock could fire multiple shots 'by a single function of the trigger,' a conclusion ATF itself rejects.
- On the second requirement: Even if the first test were met, firing multiple shots with a bump-stock rifle is not 'automatic' under §5845(b). The statute specifies that the 'single function of the trigger' must itself automatically produce multiple shots. With a bump-stock rifle, the shooter must also continuously maintain the precise amount of forward pressure on the front grip — additional manual input beyond operating the trigger. Too much or too little pressure stops the firing, so the trigger function alone is not what drives continuous fire.
- The Court distinguished pressing a machinegun's trigger down — which IS the single trigger function for a fully automatic weapon — from pushing the front grip of a bump-stock rifle, which is separate, additional input. It also compared the bump-stock rifle to the Ithaca Model 37 shotgun, which ATF itself concedes is not a machinegun because its pump action requires ongoing manual operation: maintaining forward grip pressure, the Court said, is no less additional input than working a pump.
- Finally, the Court rejected ATF's appeal to the 'presumption against ineffectiveness' — the interpretive principle disfavoring readings that make a statute easy to evade. The statute remains fully effective against all traditional machineguns; the fact that it does not reach bump stocks does not render it useless. Notably, ATF itself had consistently held for nearly a decade across more than ten separate decisions that bump stocks were not machineguns — undermining any claim that the Court's reading guts the law.