The CMMG Dissent MK4 .300 AAC Blackout 6.5" barrel pistol is a compact, modular AR-platform personal defense weapon built for shooters who need serious firepower in a tight package. Chambered in .300 BLK, it delivers .30-caliber performance without the bulk of a full rifle—ideal for home defense, vehicle carry, or close-quarters work where maneuverability matters. At just 14.7" overall and 4.8 lbs, this Coyote Tan Cerakote pistol won't slow you down, yet it punches well above its weight class thanks to CMMG's patent-pending Compact Action that eliminates the traditional buffer tube entirely.
What sets the Dissent MK4 apart is its thoughtful engineering. The upper and lower receivers are both forged 7075 T6 aluminum, built tough for years of use. The forward non-reciprocating side charger can be swapped for left- or right-handed operation—no fumbling with a traditional charging handle. Ambidextrous controls throughout mean lefties and righties both get a proper grip on this gun. The TriggerTech AR-D 2-stage trigger breaks clean, and the CMMG ZEROED linear compensator helps manage recoil in a platform this compact. At the rear, a 1913 Picatinny rail section lets you attach the brace or stock that fits your needs and legal situation.
The 6.5" barrel wears a 1:7 twist and sports an SLR adjustable .750 gas block tuned for the pistol gas port—CMMG engineered the whole system to run reliably. The 5.5" proprietary handguard keeps your support hand close and comfortable. Out of the box, you'll get a Magpul 300BLK 30-round PMAG loaded and ready. If you're building a dedicated .300 BLK pistol for serious work or you want an AR-15 platform squeezed into a PDW footprint, the Dissent MK4 delivers modularity, control, and ballistics without compromise.
| Platform | CMMG Mk4 |
| Caliber | .300 AAC Blackout |
| Barrel Length | 6.5" |
| Overall Length | 14.7" |
| Weight | 4.8 lbs |
| Barrel Twist | 1:7 |
| Barrel Material | 4140CM SBN |
| Barrel Contour | MT |
| Muzzle Device | CMMG ZEROED Linear Compensator |
| Muzzle Thread | 5/8 x 24 |
| Operating System | Compact Action—Direct Impingement |
| Gas Block | SLR Adjustable .750 |
| Gas Port Location | Pistol |
| Upper Receiver | DISSENT 7075 T6 Aluminum |
| Lower Receiver | Mk4 Forged 7075 T6 Aluminum |
| Handguard | CMMG 5.5" Proprietary |
| Charging Handle | DISSENT Side Charger (switchable) |
| Trigger | TriggerTech AR-D 2-Stage |
| Trigger Guard | CMMG ZEROED |
| Safety Selector | CMMG ZEROED 60/90 Degree (Ambidextrous) |
| Pistol Grip | CMMG ZEROED |
| Receiver Extension | 1913 Picatinny Rail End Cap |
| Magazine Included | Magpul 300BLK 30-round PMAG |
| Finish | Coyote Tan Cerakote |
The Dissent MK4 is configured as an AR pistol platform with a 1913 Picatinny rail at the rear for attaching a brace or stock. The legal classification depends on local and federal regulations; buyers are responsible for understanding their local firearms laws before purchase.
Yes. The forward non-reciprocating side charger is switchable for left- or right-handed operation, giving you flexibility based on your preference or shooting style.
The Dissent MK4 comes with a Magpul 300BLK 30-round PMAG. As a .300 BLK platform, it is compatible with magazines designed for that caliber.
CMMG's patent-pending Compact Action houses the entire recoil system in the upper receiver, eliminating the need for a traditional buffer tube. This design contributes to the pistol's ultra-compact 14.7" overall length and 4.8 lb weight while maintaining reliable direct-impingement operation.
Firearm Shipments:
To buy rifles or shotguns, you must be 18 years old, and for handguns, actions, or receivers, the minimum age is 21. By placing an order for this firearm, you confirm that you are the legitimate transferee/buyer, meet the legal age requirements, and comply with all Federal, State, and local laws and regulations necessary to purchase this firearm.
We only ship firearms to valid Federal Firearms License (FFL) holders. At checkout we provide a FFL locator for your convenience.
We will need a copy of the FFL’s license to facilitate the process, kindly request your dealer to email us a copy of their FFL, as we cannot dispatch the firearm until we receive this document. It is imperative for the buyer to choose their FFL dealer, ensure they are willing to facilitate the transfer, and have them email their FFL copy to BOSQUE Outdoors. To avoid any confusion, the customer's name or order number must be mentioned in the email containing the FFL.
Email: [email protected]
CMMG
