The CMMG Dissent Mk4 is a compact AR-style pistol chambered in .300 AAC Blackout, built around a 6.5-inch barrel and finished in tungsten Cerakote. It uses CMMG's Compact Action direct-impingement system, which places the recoil mechanism inside the upper receiver instead of a traditional buffer tube, keeping the overall package short. The pistol ships optics-ready and retains AR-15 style ambidextrous controls. 
 

Key Specifications 

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

Detailed Features 

• Bufferless Compact Action design with a forward side charging handle removes the need for a standard buffer tube 
• Adjustable gas block paired with a CMMG ZEROED linear compensator 
• DISSENT 7075-T6 aluminum upper mated to a forged Mk4 7075-T6 lower 
• Free-float M-LOK handguard with a rear 1913 Picatinny rail section for accessories 
• AR-15 style ambidextrous controls and an optics-ready upper for mounting a red dot 
   
  This configuration is aimed at shooters who want a portable .300 Blackout platform without the length of a full carbine, useful as a truck gun or a compact home-defense setup where AR-15 manual of arms is preferred.

Owners of the Dissent line tend to like how CMMG's Compact Action shrinks the package without giving up AR-15 style controls. The bufferless design draws mixed reactions: some shooters appreciate the shorter overall length and reduced weight up front, while others find the forward side charger takes a range session or two to get used to compared to a standard AR charging handle. Reliability chatter around the platform is generally positive once shooters run it with ammunition matched to the gas system.

As a compact .300 Blackout pistol, the Dissent Mk4 gets picked for close-quarters or truck-gun duty more than for extended range sessions. The optics-ready upper and M-LOK handguard make it easy to set up with a red dot and a light, and the ambidextrous controls are appreciated by left-handed shooters. Some owners note that a pistol this short benefits from a brace or arm strap for stable one-handed control, since the compact profile changes the way it points compared to a full-length carbine.

Value-wise, CMMG pistols sit at a premium over basic mil-spec AR builds because of the proprietary Compact Action parts, and owners generally accept that tradeoff for the compact footprint. Aftermarket support for standard AR-15 furniture and optics is broad, though parts specific to the Compact Action system come from CMMG itself. .300 Blackout ammunition is widely available, which keeps the platform practical to feed.