Garland v. Cargill
The Supreme Court struck down the federal bump stock ban, ruling 6–3 that bump stocks — the rifle attachments used in the 2017 Las Vegas mass shooting — do not meet the legal definition of a 'machinegun' under the National Firearms Act.
The decision means only Congress, not the ATF, can prohibit bump stocks, and the attachments are no longer federally banned unless lawmakers pass new legislation.
How it got here: Cargill surrendered his bump stocks under protest and sued ATF; a federal trial court ruled for ATF; the Fifth Circuit initially affirmed, then reversed en banc; the Supreme Court granted review to resolve a split among federal appeals courts.
The Case in Depth
What happened
Michael Cargill, a Texas gun-shop owner, surrendered two bump stocks to the ATF under protest after the agency issued a 2018 rule classifying bump stocks as illegal "machineguns" and threatening criminal prosecution for owners who refused to comply. Bump stocks are rifle accessories that harness a gun's recoil to help the shooter rapidly re-engage the trigger, enabling a rate of fire approaching that of a true machinegun. They came to national attention when a gunman used them to kill 58 people at a Las Vegas outdoor concert in 2017.
The question before the Court
Did a federal firearms agency have legal authority to ban bump stocks by classifying them as "machineguns" under a law that defines machineguns as weapons firing multiple shots automatically with a single trigger function?
The Court's answer
No — the ATF exceeded its legal authority when it issued a rule classifying bump stocks as "machineguns." Under the National Firearms Act, a machinegun is a weapon that fires more than one shot automatically "by a single function of the trigger." A bump-stock rifle doesn't satisfy that definition for two independent reasons.
First, a bump-stock rifle still requires the trigger to go through a complete mechanical cycle — press, release, reset — for every single shot. A bump stock only speeds up how quickly those separate trigger cycles happen; it does not eliminate them. Second, even setting that aside, firing multiple shots with a bump-stock rifle requires the shooter to continuously maintain the right amount of forward pressure on the front grip with a second hand — manual input beyond the trigger itself. A true machinegun fires continuously from a single trigger press alone. Because bump stocks fail both elements of the statutory definition, the ATF had no authority to ban them by redefining the word "machinegun."
Curious how the Court got there? See the step-by-step legal reasoning →
Why it matters
Bump stocks are no longer federally prohibited, and the hundreds of thousands of owners who surrendered or destroyed them under the ATF's 2018 rule have no legal recourse under this decision. The ruling also signals that federal agencies cannot stretch existing statutory definitions to cover new threats — even deadly ones — without explicit authorization from Congress.
What changes now
Bump stocks are no longer federally prohibited under existing law. People who previously surrendered or destroyed their bump stocks to comply with the ATF rule have no legal remedy under this decision. Justice Alito's concurrence expressly invites Congress to amend the statute to cover bump stocks. Several states have enacted independent bump stock bans, which this ruling does not disturb. No further proceedings in this case are necessary — the Fifth Circuit's ruling in Cargill's favor stands.
What this does not decide
The Court did not address whether a federal statute explicitly banning bump stocks would be constitutional, nor did it reach any Second Amendment question. The ruling says nothing about state-level bump stock laws. Justice Alito's concurrence underscores that Congress retains full authority to ban bump stocks through new legislation.
Concurrences and dissents
Concurrence — Justice Alito
Justice Alito joined the majority because he found the statutory text clear and binding, but wrote separately to acknowledge what the Court's ruling does not change: the human cost of bump stocks. He noted that the 2017 Las Vegas shooting demonstrated that bump stocks can be as lethal as traditional machineguns, and that this reality strengthened the argument for Congress to amend the law. He concluded that Congress — not a federal agency — holds the power to close this gap and suggested it would have done so already had ATF not tried to act unilaterally.
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's central argument that a bump-stock rifle should be called a machinegun because it functions exactly like one.
Justice Sotomayor argued the majority's interpretation defies the ordinary meaning of the statute. Using the analogy '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,' she contended that a bump-stock rifle fires 'automatically more than one shot' with 'a single function of the trigger,' just like an M16 — both require only one trigger initiation plus continuous pressure to fire repeatedly. She criticized the majority for fixating on internal gun mechanics rather than the human act of the shooter, and argued the decision makes Congress's machinegun ban readily evadable.
How the Court got there
The legal reasoning, step by step
- The National Firearms Act's definition of 'machinegun' in 26 U.S.C. § 5845(b) requires a weapon to satisfy two conditions: it must fire more than one shot (1) 'by a single function of the trigger,' and (2) 'automatically.' The Court read these as independent requirements and analyzed each separately, concluding that bump-stock rifles fail on both grounds.
- On the 'single function of the trigger' requirement: The Court defined a 'function of the trigger' as the complete mechanical cycle the trigger must undergo — pressed, released, and reset — before it can fire again. A bump-stock rifle still completes this full cycle for every shot fired. The bump stock only shortens the time between those separate cycles; it does not merge them into one. Every shot therefore results from a distinct trigger function.
- The Court rejected the ATF's counter-argument that the shooter's initial trigger pull sets off a single continuous sequence. ATF's own rule defined 'function of the trigger' to include 'analogous motions' — and if pushing the rifle forward to bump the trigger qualifies as one such motion, then every subsequent bump is its own separate trigger function. That would mean no single function fires multiple shots, undermining ATF's position on its own terms and making it internally inconsistent.
- On the 'automatically' requirement: Firing multiple shots with a bump-stock rifle requires more than just engaging the trigger — the shooter must also continuously maintain precisely the right amount of forward pressure on the front grip with the non-trigger hand. Too much or too little pressure stops the firing. This ongoing, separate manual input means the rifle does not fire multiple shots 'automatically' by a single trigger function; it fires only 'by a single function of the trigger and then some.'
- The Court reinforced this conclusion by comparing the bump stock to the Ithaca Model 37 pump-action shotgun, which the ATF itself concedes is not a machinegun because the shooter must manually operate the pump with a second hand. Maintaining forward pressure on a bump-stock rifle is no less additional manual input than pumping a shotgun, so the ATF could not coherently explain why the two cases should yield different results.
- The Court dismissed ATF's 'presumption against ineffectiveness' argument — the claim that reading bump stocks out of the machinegun definition would hollow out the law. The statute still covers every traditional machinegun; it simply does not reach this particular accessory. If Congress wants to ban bump stocks, it is free to amend the statute, which several lawmakers had already proposed to do.