The CMMG Dissent MK4 is a 6mm ARC semi-automatic rifle with a direct impingement operating system and a side-folding stock. The 6mm ARC cartridge is worth understanding before buying. It was developed with Hornady for the DoD and delivers better long-range ballistics than 5.56 at comparable rifle lengths, with a flatter trajectory and less wind drift. 
 

Key Specifications 

• Model: Dissent MK4 
• Caliber: 6mm ARC 
• Barrel Length: 16.1 inches 
• Capacity: 10+1 rounds 
• Weight: 7.70 lbs 
• Overall Length (OAL): Adjustable from 25.90 to 36.60 inches 
• Trigger Type: Zeroed Drop-In Single Stage 
• Safety Mechanism: CMMG Zeroed 60/90 Degree Safety 
• Stock Type: CMMG Dissent Side Folding Stock 
• Muzzle Device: CMMG Zeroed Muzzle Brake 
• Receiver Material: Aluminum 
• Finish Color: Midnight Bronze 
   

Detailed Features 

 
The Zeroed drop-in single-stage trigger has a clean break and is a step up from a standard mil-spec trigger. The 60/90 degree CMMG Zeroed safety selector gives ambidextrous operation and lets you choose your throw angle depending on preference or glove use. 
 
The side-folding Dissent stock is the most distinctive aspect of the platform. It folds to collapse the OAL down to 25.90", which matters for storage or vehicle transport. The 1:7.5" barrel twist rate is optimized for the 6mm ARC's heavier projectile lineup. The CMMG Zeroed muzzle brake handles recoil and muzzle rise well for follow-up shots. At 7.70 lbs it's not ultralight, but the weight is managed reasonably through the stock design. 
 

Usage Scenarios 

• Precision rifle work and medium-range target shooting benefit from the 6mm ARC's better ballistic coefficient versus 5.56. 
• The folding stock and adjustable OAL make it more practical for vehicle storage and confined-space handling than a fixed or collapsible tube. 
• Hunters running this for deer-class or varmint work get a flat-shooting round in a familiar AR-pattern platform.

The Dissent MK4 in 6mm ARC draws a mix of genuine enthusiasm and practical scrutiny.

The 6mm ARC cartridge is a recurring theme in positive feedback. Users who've done the ballistics homework appreciate the long-range performance it brings to an AR-15-pattern platform, and the 1:7.5" twist optimized for heavier bullets gets called out as the right choice for the caliber. The Midnight Bronze finish is consistently mentioned as visually distinctive. Build quality gets strong marks, consistent with CMMG's reputation. The folding stock and compact OAL when folded (25.90") draw particular attention from users who need a packable or vehicle-stored rifle.

On the critical side, price is the most common friction point. The Dissent MK4 sits at the upper end of the AR market, and not everyone agrees the feature set justifies the premium over a conventional collapsible-stock build. The 10+1 capacity limitation (where applicable) gets mentioned by users in states without magazine restrictions who see it as an unnecessary constraint on the platform. Reliability is mostly positive with occasional exceptions that appear to be batch-specific rather than systematic. Ergonomics are well-received overall, though grip and stock fit are personal enough that some users swap components immediately.