Complete upper receiver assembly for AR-15 style firearms manufactured by Fightlite Industries. The MCR (Mission Configurable Rifle) features a gas piston action along with a belt-fed feeding system that can accommodate both standard AR-15/M16 magazines or M27 linked ammunition. A quick-change barrel allows for fast barrel changes under 3 seconds. This model ships with a belt-feed main action spring, mil-spec H3 buffer, carbine stock spacer, extended bolt catch, magazine adapter and 100 M27 ammunition links.