BUSHMASTER M4A3 Flat Top 16in 5.56 Upper Receiver (91823)
- The Bushmaster M4A3 Upper Receiver, Flat Top, 16" barrel, 5.56/.223 Caliber (91823) will attach to most AR15 lower receivers on the market, and includes bolt carrier group.
- 5.56 NATO
- AR-15 (Semi Auto) bolt carrier group
- Features A2 birdcage-type flash hider to control muzzle flash
- Front sight post with bayonet lug