BCM® MK2 Standard 12.5″ 300 BLACKOUT Upper Receiver Group w/ MCMR-10 Handguard

BCM® 300 Blackout Upper Receiver Groups

Continuous taper barrel profile designed for optimal weight, balance, and performance.

Barrel profile fluted toward the rear near chamber area – Increases strength and heat dissipation.

Tapered barrel profile out front, for easier maneuverability.

No sharp handguard cap shoulder for improved barrel harmonics and improved accuracy.

Muzzle threaded in standard 30 cal (5/8×24).

Includes MCMR-10 Handguard

Includes MCMR-SM (MCMR Sling Mount)

Includes One 3″ Picatinny Rail Section

Includes BCM® Comp Mod 1 – 762/300 BLK

Featuring BCM’s Patent Pending MK2 Upper Receiver
This proprietary design offers enhanced rigidity over the USGI product.  The increased rigidity limits barrel deflection which aids in consistency/accuracy.   Less flex also reduces premature damage, wear, and failure of bolt lugs from misalignment.   A gas expansion chamber is machined above the charging handle track, combined with dual vents machined at the rear (each side, above charging handle latch) help to redirect and vent gas away the shooters face.

BCM® has taken great care to ensure the best possible performance and interchangeability. However, due to the large operational range of 300 Blackout ammunition in the market place, BCM® cannot guarantee function will all ammunition types in all conditions. These barrels were designed to run with a H3 buffer with high velocity ammo. If running subsonic ammunition, it is recommended to run your suppressor and a carbine buffer. Fine tuning may be required in limited instances based on ammo and buffer choices that work best for the desired application. BCM® also recommends running the Crane O-ring (provided with all BCM® Bolt Carrier Groups) over the extractor with 300 Blackout.