CMMG Dissent MK4 | 5.7x28mm | 6.50 in Barrel | 57BA8AEAB

The CMMG DISSENT MK4 is a compact AR-platform upper engineered around CMMG’s Compact Action and Radial Delayed Blowback technology with a fixed ejector. The design houses the action and recoil assembly in the upper receiver, reducing overall bulk and length compared with traditional AR pistol-style uppers. A forward non-reciprocating left-side charging handle allows quick manipulation without removing the shooting hand from the grip area. This configuration is well suited to range training and competitive target work where compact handling and consistent function are priorities.

Product Specifications

• The manufacturer is CMMG.
• The model is the Dissent MK4.
• The manufacturer’s part number is 57BA8AEAB.
• The caliber is 5.7 x 28 mm.
• The barrel measures 6.50 inches for compact handling.
• The barrel length range is 6 to 6.99 inches.
• The rate of twist is 1:9.
• The barrel finish is Black.
• The handguards are 4.60″ M-LOK.
• The handguard finish is Armor Black.
• The overall finish type is Armor Black.
• The upper features a forward non-reciprocating left-side charging handle.
• The muzzle device is a zeroed linear compensator.
• The assembly includes a Picatinny end plate for use in place of a buffer tube.
• The UPC is 810097509412.

The DISSENT MK4 upper delivers a compact, purpose-built option for shooters wanting a shorter AR-platform assembly without sacrificing function. Its compact action and left-side charging feature make it practical for tight-handling scenarios, while the M-LOK handguard and Picatinny end plate provide familiar mounting and interface options for accessories and lowers. If you value a modern, compact AR upper engineered for reliable operation and straightforward handling, this CMMG DISSENT MK4 configuration is designed to meet those needs.