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specifications
Cmmg
Platform:AR-15
AR-15 4.5 Barrel & Bolt Group Kit Mt 4140Cm 22Lr
| Caliber | Manufacturer | Color | Weight | Merchant Price | Merchant URL | |
|---|---|---|---|---|---|---|
| None | Cmmg | None | None None | $312.31 | Brownells | Add |
Prices last checked September 2026. Prices and availability change often, so confirm on the retailer's site.
An Easy Conversion to .22 LR for Your Upper Receiver
In this Barrel and Bolt Group Kit, CMMG provides everything you need to convert your AR-15 into a dedicated .22 LR rimfire training platform.
The barrel measures 4.5 inches long and is machined from 4140 chrome-moly steel, complete with a salt-bath nitride finish and a medium-taper profile. The barrel is optimized with a 1:16-inch twist that's compatible with most .22 LR bullets on the market, but the system runs best with 36-grain round-nose bullets.
Each .22 LR Barrel and Bolt Group Kit from CMMG also features a .22 LR sporting chamber, as well as a threaded muzzle measuring 1/2-28 TPI thread pitch. CMMG recommends using a round-style hammer in place of a notched hammer to avoid function issues. The only other piece of the kit needed for a functioning system is a dedicated .22 LR magazine.