Geissele Super Duty MOD 1 11.5" 5.56/223 AR-15 Complete Upper Receiver is built for hard use in short-barrel rifle or pistol configurations. The 11.5-inch barrel is Cold Hammer Forged from CMV steel and features a 1:7 twist rate, chrome lining, and a carbine-length gas system. This setup ensures optimal performance in suppressed and unsuppressed roles while maintaining reliability across a variety of ammo types and conditions.

Included is the 10.5-inch MK16 Super Modular Rail (SMR), which offers robust M-LOK compatibility and excellent rigidity for mounting optics, lights, or IR systems. The upper is finished in Geissele’s Desert Dirt Color (DDC) anodizing and comes with a Geissele Reliability Enhanced Bolt Carrier Group and Airborne Charging Handle. Designed for both duty use and high-performance builds, this upper is engineered to exceed expectations on every front.