CMMG 30D810A 8-inch .300 AAC Blackout Barrel Sub-Assembly

Description

The CMMG 30D810A barrel sub-assembly is a pistol-length option for building compact AR-15 uppers chambered in .300 AAC Blackout. It ships with a properly installed M4 barrel extension and is headspaced at the factory for immediate installation into a compatible upper. The barrel features a medium tapered profile and a durable salt-bath nitride finish over 4140 chromoly steel for wear resistance and corrosion protection.

Key Specifications

• The barrel length is 8 inches for compact handling and short-barrel setups.
• The cartridge is .300 AAC Blackout for suppressed and short-barrel performance.
• The twist rate is 1:7 to stabilize a wide range of bullet weights.
• The material and finish are 4140 chromoly steel with a salt-bath nitride finish for durability.
• The profile is a medium tapered contour for balanced weight and rigidity.
• The muzzle threads are 5/8-24 for common .30-caliber muzzle devices and suppressors.
• The gas system is pistol length designed for short gas system configurations.
• The gas block journal accepts a .750 diameter gas block.
• The unit ships with an installed M4 barrel extension and is factory headspaced.
• The weight is approximately 1.5 lbs for lightweight upper builds.

Designed for builders who need a reliable, compact AR-15 barrel for short-barrel or suppressed applications, this CMMG sub-assembly pairs proven materials and manufacturing with practical features like 5/8-24 muzzle threads and a 1:7 twist. Its nitride-treated 4140 chromoly construction offers corrosion resistance and extended service life while the medium taper profile keeps weight under control. Ideal for precision short-range shooting and compact rifle builds where dependable, consistent performance is required.