The Supreme Court overturned a federal ban on bump stock devices, which allow semiautomatic guns to shoot fast, in a 6-3 ruling on Friday. This decision overturns one of the few recent federal efforts to combat gun violence. The conservative majority contended that bump stocks do not qualify as machine guns under a 1986 regulation that prohibits civilian ownership of such firearms. The Trump administration revised this rule in 2018, after a gunman killed 60 people in Las Vegas using bump stocks. In her dissent, Justice Sonia Sotomayor cautioned that the ruling could have “deadly consequences,” undermining attempts to prevent shooters from using machine guns.