Steel adapter allows you to install muzzle brakes and flash hiders on a Sam 7k AK -47 tactical rifle with an un-threaded barrel. No machining necessary. With three machined set screws it can be secured to barrel easily and can be welded permanent as well. Adapter features 14mm-1.0 (LH) left hand threads for 7.62x39 caliber AK-47 and SKS rifles. Adapter hole for the bullet is only .343" Fits Sam 7K non threaded barrels.