FILE - An employee of North Raleigh Guns demonstrates how a bump stock works at the Raleigh, N.C., on Feb. 1, 2013. Gun accessories known as bump stocks hit the market more than a decade ago. The U.S. government initially concluded that the devices that make semi-automatic weapons fire faster didn't violate a federal ban on machine guns. That changed after a gunman with bump stock-equipped rifles killed 60 people and wounded hundreds in Las Vegas in 2017. (AP Photo/Allen Breed, File)
FILE - Shooting instructor Frankie McRae demonstrates the grip on an AR-15 rifle fitted with a "bump stock" at his 37 PSR Gun Club in Bunnlevel, N.C., on Oct. 4, 2017. Gun accessories known as bump stocks hit the market more than a decade ago. The U.S. government initially concluded that the devices that make semi-automatic weapons fire faster didn't violate a federal ban on machine guns. That changed after a gunman with bump stock-equipped rifles killed 60 people and wounded hundreds in Las Vegas in 2017. (AP Photo/Allen G. Breed, File)
FILE - A bump stock is displayed in Harrisonburg, Va., on March 15, 2019. The Supreme Court will hear a challenge Wednesday, Feb. 28, to a Trump-era ban on bump stocks, a gun accessory used in a Las Vegas massacre that was the deadliest mass shooting in modern U.S. history. (AP Photo/Steve Helber, File)