Cmmg Bbl Sub-Assm 22Arc 20 Mt 4140Cm Sbn

The CMMG .22 ARC barrel assembly puts modern cartridge performance in your AR-15 platform rifle. Built around the .22 ARC caliber—a bottleneck round designed to stabilize and launch heavier .22 projectiles with authority—this 20-inch barrel sub-assembly lets you explore one of the more interesting intermediate cartridges without a complete rifle purchase. If you're already invested in the AR-15 ecosystem and curious about what .22 ARC can do, swapping in this barrel is the fastest way to experiment with its flatter trajectory and energy retention compared to traditional .22 centerfire rounds.

The 4140CM steel construction with nitride finish gives you a robust barrel that handles brass loads and resists corrosion and wear. The 1:7 twist rate is optimized for the heavier bullets that make .22 ARC interesting—think 80- to 90-grain projectiles and up—so you're not fighting a barrel twist that wants to slow them down. The MT contour keeps weight reasonable while maintaining rigidity, and the 1/2 x 28 muzzle thread is AR-standard, so your existing suppressors or muzzle devices will fit without adapters.

Gas port location is set for rifle-length operation, so function is tuned for the typical AR-15 gas tube system. This is a sub-assembly, meaning it comes ready to install on a compatible upper receiver—no smithing required if you already have the receiver and other components. Whether you're building a dedicated .22 ARC upper, setting up a dedicated training rifle, or just want to run a different cartridge on your existing lower, this barrel assembly gives you a straightforward path into the cartridge.

Key Features

• .22 ARC caliber optimized for heavier .22 projectiles
• 20-inch barrel length for practical velocity and accuracy
• 1:7 twist rate engineered for .22 ARC bullet weights
• 4140CM steel with nitride finish for durability and corrosion resistance
• 1/2 x 28 muzzle thread for standard AR accessories
• Rifle-length gas port for AR-15 direct impingement systems
• MT contour balances weight and stiffness

Specifications

Frequently Asked Questions

Will this barrel assembly work on my existing AR-15 upper?

This is a sub-assembly designed for the AR-15 platform, but you'll need a compatible upper receiver. Verify that your upper is chambered for or can be fitted for .22 ARC before installation.

What suppressors or muzzle devices fit this barrel?

The 1/2 x 28 muzzle thread is standard for AR-15 .22 caliber rifles, so it will accept any muzzle brake, flash hider, or suppressor threaded to that specification.

What is .22 ARC and why use it?

.22 ARC is a bottleneck centerfire cartridge designed to fire heavier .22 caliber bullets (typically 80–90 grains and up) with improved ballistics compared to traditional .22 centerfire options. The 1:7 twist in this barrel is engineered to stabilize those heavier projectiles for better downrange energy and accuracy.

Is this a complete upper receiver?

No, this is a barrel sub-assembly. You'll need to attach it to a compatible AR-15 upper receiver with the appropriate bolt carrier group and charging handle for a complete upper.