United States Supreme Court
A semi-automatic rifle equipped with a bump stock is not a "machine gun" as defined by federal law; the ATF's bump stock ban exceeded its statutory authority.
Garland v. Cargill held that the ATF's regulation banning bump stocks — which allow semi-automatic rifles to fire at rates similar to machine guns — exceeded the agency's statutory authority because bump-stock-equipped rifles do not meet the federal statutory definition of "machine gun."