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 to prevent firing unless locked in place, eliminating the dangers of its blowback action predecessors. It features minimal moving parts, easy maintenance, 18" barrel, controlled round feed. (Two 10-round magazines included)
*Check with your trigger manufacturer for compatibility with rimfire cartridges.