CMMG RESOLUTE MK4 Upper Group - 5.56 NATO, 16.1" Barrel, Armor Black Cerakote Top off your next AR15 build with the CMMG RESOLUTE MK4 Upper Group, chambered in 5.56x45mm and finished in a sleek Armor Black Cerakote. This complete upper group is built on a billet 6061 T6 aluminum upper receiver and pairs a 16.1-inch 4140CM steel barrel with a 1:7 twist rate and Salt Bath Nitride (SBN) finish for outstanding durability and corrosion resistance. The Mid-length gas system feeds through a 0.750 non-adjustable gas block, providing reliable and consistent cycling. The CMMG EML15 M-LOK handguard offers a streamlined profile with ample mounting real estate for accessories. Ready to mate with any AR15 lower group of your choice, this upper ships complete with a bolt carrier group and a full suite of CMMG ZEROED accessories, making it an ideal foundation for a reliable and accurate rifle build. Product Highlights Complete Build-Ready Upper: Includes bolt carrier group, ZEROED AR15 Polymer Dust Cover, ZEROED Ambi Charging Handle, and ZEROED Muzzle Brake 5.56mm for an out-of-the-box ready experience. Billet 6061 T6 Aluminum Upper Receiver: Precision-machined for tight tolerances, superior strength, and a refined fit with any mil-spec AR15 lower group. 4140CM SBN Barrel: The 16.1-inch medium taper barrel features a salt bath nitride finish and a 1:7 twist rate, optimized for accuracy and longevity with 5.56x45mm ammunition. CMMG EML15 M-LOK Handguard: Lightweight and free-floating design with M-LOK attachment points for easy customization with lights, grips, and other accessories. Lifetime Quality Guarantee: Every CMMG product is backed by their Lifetime Quality Guarantee against material and workmanship defects, ensuring lasting peace of mind. Specifications Brand: CMMG Platform: Mk4 Caliber: 5.56x45mm (223 Rem / 5.56 NATO) Operating System: Direct Impingement Barrel Length: 16.1 inches Barrel Twist: 1:7 Barrel Contour: MT (Medium Taper) Barrel Material: 4140CM, Salt Bath Nitride (SBN) Muzzle Device: CMMG ZEROED Muzzle Brake Muzzle Thread: 1/2 x 28 Gas Port Location: Mid Gas Block: 0.750 Non-Adjustable Upper Receiver: Billet 6061 T6 Aluminum Handguard: CMMG EML15 M-LOK Finish: Cerakote Standard - Armor Black Charging Handle: CMMG ZEROED Ambi Weight: 4.3 lbs Overall Length: 25 inches MPN: CMM55BC7C3AB UPC: 810097503823 Disclaimer: 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.