Product DescriptionThe CMMG Replacement Barrel Kit with Bolt Carrier Group is a complete solution for converting your existing upper into a dedicated .22 Long Rifle setup. Built around a 16.1-inch M4-profile barrel made from chrome-moly steel with a durable black nitride (salt bath nitride) finish, this kit is designed to deliver reliable rimfire performance in AR-15/Mk4 platforms. Add a compatible magazine and you're ready to run; for best results, CMMG recommends a round-style hammer (notched hammers may cause function issues) and notes that 36-grain plated nose bullets have proven to be a strong choice for reliable cycling.Product Highlights All-in-one barrel and bolt group kit to convert an existing upper to dedicated .22 Long Rifle 16.1-inch M4-profile 4140 chrome-moly barrel with black nitride (salt bath nitride) finish inside and out 1:16 twist rate and .22 Long Rifle sporting chamber for consistent rimfire performance Threaded muzzle (1/2x28) for compatibility with many common .22-caliber muzzle devices Designed to fit AR-15/Mk4 platforms; magazine sold separatelySpecs Brand: CMMG Manufacturer Part Number: 22D7C6C UPC: 815835013985 Caliber: .22 Long Rifle Barrel Length: 16.1 in (16.10 in) Profile: M4 Barrel Material: 4140 chrome-moly steel Finish: Black Nitride / Salt Bath Nitride Twist Rate: 1:16 Chamber: .22LR Sporting Chamber Muzzle Threads: 1/2x28 Gas Block Journal Diameter: 0.750 in (carbine-length journal) Included Components: Barrel and Bolt Carrier Group (BCG) Fitment: AR-15 / Mk4 Weight: 2.0 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.