Product DescriptionThe CMMG Replacement Barrel Kit with Collar is built for shooters who want to assemble a dedicated .22 LR AR-15 upper with proven CMMG compatibility. This 16.1-inch M4-contour barrel is made from durable 4140 chrome moly/chromoly steel and finished in a black nitride (salt bath nitride) treatment for corrosion resistance. It includes the barrel collar needed to replace the chamber adapter on a .22 AR conversion and to support a dedicated .22 LR bolt carrier group (BCG) build.Product Highlights Purpose-built replacement barrel kit for dedicated .22 LR AR-15 upper assemblies Includes barrel collar to replace the chamber adapter on .22 AR conversions 16.1-inch M4 contour with 1:16 twist optimized for .22 Long Rifle 4140 chrome moly/chromoly steel construction with black salt bath nitride finish Threaded 1/2"-28 muzzle for common rimfire muzzle devices and suppressor mountsSpecs Brand: CMMG Manufacturer Part Number: 22D7C4A UPC: 815835014944 Caliber: .22 Long Rifle (.22 LR) Barrel Length: 16.1 in (16.10 in stated) Material: 4140 Chrome Moly/Chromoly Steel Finish: Black Nitride / Black Salt Bath Nitride Twist Rate: 1:16 Barrel Contour: M4 Muzzle Threads: 1/2"-28 Gas Block Diameter / Journal: 0.750 in Compatibility: AR-15 (dedicated .22 LR upper build) Included: Barrel collar Chrome Lined: No Shipping Weight (approx.): 1.96 lbDisclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product's manufacturer.