LWRCI ICMKII A5 .300 Blackout 10" Bbl Black SBR Upper ICMKIIU3B10

The LWRCI ICMKII A5 .300 Blackout 10″ SBR Upper in Black is a high‑end AR‑pattern upper receiver built around LWRC International’s proprietary short‑stroke gas piston A5 system, engineered for reliability and ease of maintenance in compact configurations. Designed for the versatile .300 AAC Blackout cartridge, it features a cold‑hammer‑forged 10″ barrel with a 1:7″ twist rate and 5/8″‑24 TPI threaded muzzle paired with a low‑profile, two‑position adjustable gas block that allows tuning for suppressed or unsuppressed use. Finished in black Cerakote for corrosion resistance and enduring performance, this upper includes a monoforge one‑piece receiver with integrated free‑float M‑LOK rail, LWRCI Skirmish backup iron sights, and an ambidextrous charging handle. Sold as an upper‑only assembly, it’s ideal for building a custom short‑barreled rifle (SBR) when paired with a compliant lower and NFA tax‑stamp approval.