The GFD AR-15 .17 HMR is a gas-operated, locking bolt, semi-automatic rimfire upper receiver for the AR-15 rifle. It is designed not to fire unless locked in place, eliminating the dangers of its blowback action predecessors. It features minimal moving parts, easy maintenance, 18" barrel, and full military specs. (Two 10-round magazines included)
*Check with your trigger manufacturer for compatibility with rimfire cartridges.