CMMG 22LR 16.1" M4 Replacement Barrel & Collar Kit - Model 22D7C4A

The CMMG 22LR 16.1" M4 Replacement Barrel & Collar Kit is built for shooters who want to build or upgrade a dedicated .22 LR AR-15 upper receiver. Whether you're assembling a custom 22LR AR from scratch or retrofitting an existing 22AR conversion system, this barrel kit gives you the core components in one package: a 16.1-inch M4-profile barrel plus the collar needed to replace a chamber adapter on conversion uppers. It's a practical, affordable way to get into rimfire AR shooting or expand your existing platform.

Built on a proven 4140 chrome-moly steel foundation, the barrel features a salt bath nitride finish inside and out—armor-hard protection that handles repeated cleaning and shooting without degrading. The 1:16 twist rate is optimized for standard .22 LR ammunition, and the half-minute-of-angle thread pattern (1/2-28") accepts common rimfire suppressors and muzzle devices. The carbine-length (.750") gas journal keeps the profile consistent with standard M4-style build conventions, so it integrates cleanly with common upper and handguard combinations.

CMMG's reputation in the rimfire conversion and dedicated 22LR AR space is well earned. This barrel kit is a no-nonsense component—not flashy, but precisely dimensioned and finished to last through thousands of rounds. Ideal for plinkers, small-game hunters, training on a budget, or anyone running an AR platform who wants a low-recoil, low-report second upper that shares controls and ergonomics.