The CMMG Dissent MK4 is a semi-automatic pistol chambered in .300 AAC Blackout, built around a direct impingement action with a compact layout. At 4.6 lbs and a 6.5-inch barrel, it handles well in tight quarters while still running the .300 BLK cartridge effectively with both subsonic and supersonic loads. 
 

Key Specifications 

• Model: Dissent MK4 
• Caliber: .300 AAC Blackout 
• Barrel Length: 6.5 inches 
• Capacity: 30+1 rounds 
• Finish: Black Nitride 
• Weight: 4.6 lbs 
   

Detailed Features 

 
The barrel is 4140CM steel with a 1:7 twist rate, which stabilizes the full range of .300 BLK projectile weights. CMMG includes their Zeroed Linear Compensator to direct blast forward and reduce felt push. The adjustable gas block lets you tune cycling for suppressed or unsuppressed use, or dial it in for a specific load. Controls are ambidextrous, and the black polymer grip is comfortable for extended handling.

Owners of the CMMG Dissent MK4 in .300 Blackout tend to land positively, with some nuance around price.

The compact size gets consistent praise. People running it for home defense or as a truck gun appreciate how manageable it is in confined spaces. The .300 Blackout caliber choice also draws a lot of support, particularly from suppressor users who note it cycles subsonic loads cleanly and handles supersonic without issues.

Build quality is generally trusted. CMMG's reputation carries weight, and most buyers find the Dissent lives up to it. Recoil is described as light and manageable, and accuracy at practical ranges comes up frequently as a strength. The ambidextrous controls and overall ergonomics are called out as user-friendly by both newer and experienced shooters.

Customization is a common topic. Optics, lights, and grip mods are popular, and the community shares a fair number of build notes. On price, opinions split: some feel the features justify the cost, others compare it unfavorably to cheaper AR pistol options in the same caliber.