Garland v. Cargill
The Supreme Court ruled 6-3 that the federal government's ban on bump stocks exceeded its legal authority, because bump-stock-equipped rifles do not meet the statutory definition of a 'machinegun' under the National Firearms Act.
The decision reinstates bump stocks as legal under federal law and makes clear that only Congress — not federal regulators acting on their own — can expand the machinegun ban to cover these accessories.
How it got here: A federal district court ruled for ATF; the Fifth Circuit initially affirmed but reversed on rehearing en banc; the government petitioned the Supreme Court to resolve a split among federal appeals courts.
The Case in Depth
What happened
After a gunman used semiautomatic rifles equipped with bump stocks to kill 58 people and wound over 500 at a Las Vegas concert in 2017, the federal Bureau of Alcohol, Tobacco, Firearms and Explosives reversed its longstanding position and issued a rule classifying bump stocks as illegal "machineguns." A Texas man named Michael Cargill surrendered two bump stocks under protest and then sued, arguing the ATF had no legal authority to redefine bump stocks under the existing machinegun statute.
The question before the Court
Did federal regulators have the legal authority to classify bump stocks — accessories that let semiautomatic rifles fire at near-machinegun speeds — as illegal "machineguns" under a 1934 federal gun law?
The Court's answer
No — the ATF did not have the authority to classify bump stocks as "machineguns" under the National Firearms Act. The statute defines a machinegun as a weapon that fires "automatically more than one shot… by a single function of the trigger," and the Court ruled that a bump-stock-equipped semiautomatic rifle satisfies neither condition. Because a shooter must release and reset the trigger between each shot — even with a bump stock — every shot results from a distinct trigger function, not a single one. A bump stock only speeds up how fast those separate trigger functions can happen.
Even setting that aside, the Court found that bump-stock fire is not truly "automatic" because the shooter must continuously maintain precise forward pressure on the rifle's front grip to keep firing. That is manual input beyond the trigger itself — something a genuine machinegun does not require. Congress chose to define "machinegun" by the mechanics of trigger function, not by rate of fire, and the ATF cannot rewrite that definition through regulation.
Curious how the Court got there? See the step-by-step legal reasoning →
Why it matters
Bump stocks, which allow semiautomatic rifles to fire hundreds of rounds per minute, are now legal to own under federal law. People who surrendered or destroyed bump stocks under the 2018 federal rule have no legal recourse. The ruling also limits the ATF's ability to use existing statutes to regulate novel firearm accessories, placing the burden squarely on Congress to pass new legislation if it wants to ban them.
What changes now
The Fifth Circuit's ruling against ATF's bump stock ban stands, and bump stocks are once again legal under federal law. People who previously surrendered or destroyed bump stocks under the 2018 rule have no legal remedy from this decision. For bump stocks to be federally banned, Congress would need to amend the National Firearms Act — something Justice Alito explicitly invited in his concurrence. Questions about whether other rapid-fire accessories (such as "forced reset triggers") also fall outside the machinegun definition may be litigated in future cases.
What this does not decide
The Court decided only whether bump stocks fit the existing statutory definition of "machinegun" — it expressed no view on whether bump stocks are dangerous or should be prohibited. Traditional machineguns remain fully banned. The ruling does not prevent Congress from passing new legislation specifically targeting bump stocks or other rapid-fire accessories, and it does not address state-level regulations.
Concurrences and dissents
Concurrence — Justice Alito
Justice Alito joined the majority because, in his view, the statutory text leaves no other reasonable reading. He acknowledged, however, that Congress in 1934 almost certainly would have viewed a bump-stock rifle as no different from a machinegun, and that the 2017 Las Vegas massacre strengthened the case for updating the law. He called on Congress to act directly now that the regulatory path has been foreclosed.
Dissent — Justice Sotomayor
“When I see a bird that walks like a duck, swims like a duck, and quacks like a duck, I call that bird a duck.”The dissent arguing that a bump-stock rifle plainly meets the ordinary-meaning definition of a machinegun.
Justice Sotomayor argued that a bump-stock-equipped rifle plainly fires 'automatically more than one shot… by a single function of the trigger' under the ordinary meaning of those words. The majority's reading fixates on the gun's internal mechanics while ignoring what the shooter actually does: pull the trigger once and maintain pressure for continuous fire. She would have upheld the ATF rule, warning that the majority's narrow definition makes Congress's machinegun ban readily evadable and will have deadly consequences.
How the Court got there
The legal reasoning, step by step
- The Court began with the text of the National Firearms Act's definition of 'machinegun': a weapon that fires 'automatically more than one shot, without manual reloading, by a single function of the trigger.' The definition sets two distinct requirements — firing multiple shots by a single trigger function, and doing so automatically — and the Court analyzed each in turn.
- On the first requirement, the Court interpreted 'function of the trigger' as the complete mechanical cycle in which the trigger is pressed, activates the firing mechanism, and then resets. With any semiautomatic rifle, whether or not it has a bump stock, the trigger must reset and be reengaged before each new shot. A bump stock only shortens the time between those distinct, separate trigger functions — it does not collapse them into one.
- The Court rejected ATF's argument that a shooter's initial trigger pull kicks off a continuous firing 'sequence' requiring only a single trigger function. ATF's own rule defined 'single function of the trigger' to include 'analogous motions,' and ATF conceded that sliding the rifle forward — the bumping motion — qualifies as such a motion. If each bump counts as a trigger function, then each shot involves a separate function, which defeats ATF's argument on its own terms.
- On the second requirement ('automatically'), the Court found that firing multiple shots with a bump stock requires manual input beyond the trigger: the shooter must actively maintain precisely the right amount of forward pressure on the rifle's front grip. Too much pressure prevents the trigger from resetting; too little means no bump. This extra ongoing action distinguishes a bump-stock rifle from a true machinegun, which fires multiple rounds once the trigger is engaged without any additional manual effort.
- The Court compared a bump-stock rifle to the Ithaca Model 37 shotgun — a gun ATF concedes cannot fire 'automatically' — because both require the shooter to perform a separate manual action with the nontrigger hand to keep firing. Maintaining forward pressure on a bump-stock rifle's grip is no less 'additional' than working the Model 37's pump action.
- Finally, the Court dismissed ATF's argument that reading bump stocks out of the statute would make the machinegun ban pointless. The statute still fully covers traditional machineguns; it simply does not extend to every weapon capable of rapid fire. Congress could have defined 'machinegun' by rate of fire but did not — and courts cannot rewrite the text based on speculation about what Congress might have intended.