Product DescriptionThe CMMG DISSENT MK4 complete upper group in 5.7x28mm is purpose-built for compact AR-platform builds without the bulk of a traditional buffer-tube recoil system. Using CMMG's patent-pending Compact Action and Radial Delayed Blowback technology with a fixed ejector, the entire action and recoil assembly is housed in the upper receiver for a shorter overall package. A forward, non-reciprocating left-side charging handle supports fast, efficient manipulation while staying on target. This upper is finished in Armor Black and includes a CMMG Zeroed Linear Comp, a 4.60" M-LOK handguard, and a 1913 Picatinny rail end plate for streamlined compatibility with AR-style lowers.Product Highlights Compact DISSENT design houses the action and recoil assembly in the upper receiver to reduce overall length Radial Delayed Blowback system with fixed ejector for smooth operation in 5.7x28mm Forward non-reciprocating left-side charging handle for quick manipulation without breaking your sight picture Armor Black finish with 4.60" M-LOK handguard for lightweight accessory mounting Includes 1913 Picatinny rail end plate to replace the buffer tube and support modern brace/stock adaptersSpecs Brand: CMMG Model: DISSENT Series: MK4 Type: Complete Upper Group / Upper Receiver Assembly Caliber: 5.7x28mm Barrel Length: 6.50" Twist Rate: 1:9 Muzzle Device: CMMG Zeroed Linear Compensator Thread Pattern: 1/2"-28 TPI Handguard: 4.60" M-LOK Charging Handle: Left-side, forward, non-reciprocating side charger Receiver Material: 7075-T6 Aluminum Finish: Armor Black (receiver/handguard) Compatibility: AR-Platform (MK4/Mil-Spec AR-15 lower; also compatible with CMMG MK57 lower) Included: Bolt carrier group (BCG) and 1913 Picatinny rail end plate UPC: 810097509412 Manufacturer Part Number: 57BA8AEABDisclaimer: 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.