FILE - In this Oct. 4, 2017, file photo, 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. The largest manufacturer of bump stocks, which allow semi-automatic weapons to fire rapidly like automatic firearms, announced Wednesday, April 18, 2018, that it will stop taking orders and shut down its website next month. (AP Photo/Allen G. Breed, File)