Reliable performance and affordable accuracy, that's what CMMG's Mk4 K .300 Blackout Upper Group adds to your firearm. CMMG's RKM11 KeyMod free-floating handguard protects fingers from hot metal. The 12.5" barrel is crafted of nitrided 4140 chromoly steel with an accuracy-enhancing 1:7 rate of twist. Muzzle features a removable A2 compensator attached with 5/8"-24 threading. Forged 7075-T6 aluminum M4-type upper receiver. Pistol gas port. Covered by CMMG's lifetime quality guarantee. Made in USA.
Note: Upper used on rifle lower receiver must be accompanied with approved NFA paperwork showing legal possession of short-barrel rifle.