Garland v. Cargill

Following the 2017 Las Vegas mass shooting, the ATF issued a rule reclassifying bump stocks as "machine guns," effectively banning them under the National Firearms Act. Michael Cargill, a gun shop owner, surrendered his devices and sued, arguing the ATF exceeded its statutory authority. The case escalated to the Supreme Court, where the central issue was whether a semi-automatic rifle equipped with a bump stock qualifies as a "machine gun," legally defined as a weapon that fires automatically more than one shot by a single function of the trigger. The Court examined the mechanical function of a bump stock, which uses recoil energy to "bump" the trigger against the shooter's stationary finger, requiring the trigger to reset between shots.

In a 6-3 decision along ideological lines, the Supreme Court struck down the federal bump stock ban. The conservative majority, led by Justice Clarence Thomas, held that a semi-automatic rifle with a bump stock does not fire "automatically" by a single function of the trigger, and therefore does not meet the legal definition of a machine gun.

The primary legal dispute was whether the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) overstepped its authority by interpreting the statutory definition of a "machine gun" to include bump stocks, or whether Congress needed to pass a new law to ban the devices.

The ruling was celebrated by gun rights advocates as a major victory against federal regulatory overreach but condemned by gun control supporters and the Biden administration. It reignited a fierce political debate in Congress regarding legislative action on firearm accessories, as the decision clarified that only lawmakers, not federal agencies, can expand the definition of illegal weapons.