The CMMG Dissent Mk4 (30A2D0F-MB) is a semi-automatic AR-pattern pistol chambered in .300 AAC Blackout. It runs a 6.5-inch barrel and CMMG's bufferless Compact Action direct-impingement system, which moves the recoil mechanism into the upper receiver and removes the need for a buffer tube. The pistol wears a Midnight Bronze Cerakote finish over its 7075-T6 forged aluminum receivers. 
 

Key Specifications 

• Brand: CMMG 
• Model: Dissent Mk4 
• Caliber: .300 AAC Blackout 
• Action: Semi-Auto 
• Capacity: 30+1 
• Barrel Length: 6.5 in 
• Receiver Material: 7075-T6 Aluminum 
• Finish: Midnight Bronze Cerakote 
   

Detailed Features 

• 6.5-inch 4140CM barrel with a 1:7 twist and salt bath nitride treatment pairs with an adjustable .750 gas block for tuning reliability across different loads. 
• CMMG Compact Action design houses the recoil spring in the upper receiver, removing the buffer tube for a shorter overall package. 
• CMMG ZEROED linear compensator is mounted on 5/8x24 threads at the muzzle. 
• Includes a Magpul 30-round PMAG loaded for .300 BLK. 
• DISSENT/Mk4 7075-T6 forged receivers carry AR-pattern controls for a familiar manual of arms.

Owners of compact AR-pattern pistols like the Dissent Mk4 in .300 Blackout tend to focus on how the bufferless design changes handling. Without a buffer tube, the platform feels shorter and better balanced one-handed, which is the main reason many shooters choose this style of gun. Feedback on CMMG's Compact Action system is generally positive, though some owners note a bufferless action needs a properly tuned gas system, which is why an adjustable gas block matters to this crowd.

Ergonomics get mixed reviews. The shorter package is easier to store and maneuver in tight spaces, but recoil impulse on a lightweight .300 Blackout pistol without a stock can feel snappier than on a full-size rifle, especially with supersonic ammunition. Shooters who add a brace or arm strap generally report better control.

On value, CMMG guns in this class are seen as a premium option. Buyers accept a higher price for the compact design and finish quality, and Midnight Bronze in particular draws compliments as a finish choice. Some owners wish threaded muzzle devices and included magazines were more standardized across CMMG's finish options.