Cmmg Bbl 300blk 16.1" Mr 4140cm Blem

The CMMG Bbl 300blk 16.1" Mr 4140cm Blem is a precision rifle barrel engineered for shooters who demand reliability in intermediate-distance engagements. Chambered in .300 Blackout, this 16.1-inch barrel delivers the subsonic performance and ballistic efficiency that law enforcement tactical teams and military personnel depend on for suppressed fire operations. Built to exacting standards, this barrel integrates seamlessly into modern AR-platform rifles and serves operators running dedicated .300 Blackout builds or conversion uppers.

Machined from premium 4140 chromoly steel, the barrel features a rigorous salt bath nitride finish—a military-grade surface treatment that resists corrosion, extends bore life, and maintains dimensional stability under sustained fire. The 1:7 twist rate is optimized for the full spectrum of .300 Blackout ammunition, from heavy subsonic rounds to lighter supersonic loads, ensuring consistent accuracy across loadings. The 5/8"-24 TPI threaded muzzle accommodates industry-standard suppressors and muzzle devices, making this barrel ideal for sound-signature management in tactical environments. Weighing just 2.25 pounds, it balances mass efficiency with the rigidity necessary for precision shooting.

This barrel excels for AR-15 and AR-10 platform builds targeting close-quarters combat, urban operations, and suppressed hunting applications. Installation is straightforward using standard AR-15 barrel extension tooling and a properly torqued barrel nut; no special gunsmithing is required. The blemish classification reflects cosmetic packaging damage only—the barrel itself is full-spec and fully functional. Users can confidently pair this barrel with quality gas tubes, bolts, and charging handles to assemble a combat-ready upper that delivers reliability, accuracy, and hearing-safe performance in the field.