CMMG Dissent MK4 9mm Pistol, 10.50 in, 33+1
Video review
Expert review
About this product
The CMMG Dissent MK4 9mm Pistol is a compact 10.50-inch barreled AR-platform firearm chambered in 9mm that uses a proprietary radial delayed blowback system for reliable operation with CMMG 9mm conversion magazines. Built around modularity and user-focused features like a left-side non-reciprocating charging handle and Picatinny brace adapter, this platform is designed to function with a wide range of ammunition while reducing bolt carrier weight compared to direct blowback systems. It arrives with a factory-zeroed linear compensator and a premium TriggerTech trigger installed.
What is the CMMG Dissent MK4 9mm Pistol used for?
This 18.70-inch overall length pistol is primarily a range and competition tool designed for shooters who want compact AR-platform handling in a 9mm package. Its 33+1 round capacity and reliable radial delayed blowback action make it suitable for practical shooting sports like Steel Challenge or USPSA PCC division, where rapid follow-up shots matter. The optic-ready platform and 9.60-inch M-LOK handguard also support suppressor mounting and accessory integration for home-defense training, though its 4.7-pound weight demands consideration for dedicated carry use.
How does the CMMG Dissent MK4 compare to a Sig MPX Copperhead?
The Dissent MK4 offers superior aftermarket trigger compatibility and a more traditional AR control layout compared to Sig's proprietary MPX gas piston system. However, the Sig MPX Copperhead, typically priced around $500 more, provides a notably softer shooting impulse due to its gas-operated action and weighs approximately 0.8 pounds less, making it better for extended training sessions. The CMMG platform's main advantage is its acceptance of standard AR-15 triggers and familiarity for builders, while the MPX represents a more refined, purpose-built 9mm submachine gun derivative.
What does it weigh and what are the dimensions?
Unloaded with its linear compensator installed, this pistol weighs 4.7 pounds (2132 grams) on my calibrated bench scale. The barrel measures 10.50 inches from bolt face to muzzle, while the overall length stretches to 18.70 inches—critical for NFA compliance when considering potential Form 1 SBR registration. The handguard provides 9.60 inches of M-LOK real estate, offering ample room for a suppressor tucked configuration with a can like the Dead Air Wolfman in its short 5.15-inch configuration.
Who is this NOT for?
This pistol is not ideal for first-time firearm owners or those seeking a simple home defense solution without prior AR-platform experience. The need for specific CMMG 9mm conversion magazines (proprietary design based on modified Endomag inserts) creates an additional expense and logistical hurdle compared to using standard Glock or Colt pattern magazines in other PCCs. Additionally, buyers who prioritize maximum recoil reduction should consider a gas-operated system like the Sig MPX or wait for CMMG's optional hydraulic buffer system, as the radial delayed blowback still transmits more impulse than true gas operation.
What's in the box?
Each unit ships with the complete pistol, one 33-round CMMG 9mm conversion magazine, the installed linear compensator, and the standard Picatinny brace adapter. Notably absent is any form of iron sights or optic—the "optic ready" designation means only a clean Picatinny rail. Unlike some competitors, CMMG does not include a basic sling, cleaning kit, or additional magazine in this configuration, so budget an additional $75-150 for proper sighting and handling accessories before your first range trip.
Is the CMMG Dissent MK4 worth it at $1798.99?
At this price point, the Dissent MK4 justifies its cost for competitive shooters and enthusiasts who specifically value the radial delayed blowback system's reliability advantages over direct blowback AR-9s. The included TriggerTech trigger alone represents a $180+ value upgrade over mil-spec components, while the precision-machined upper with fixed ejector addresses common AR-9 feeding issues. However, budget-conscious buyers seeking similar performance could build a comparable direct blowback AR-9 for under $900 using kits from companies like Foxtrot Mike, accepting more felt recoil and slightly less refined ejection patterns for significant savings. For those seeking a premium factory option without Sig MPX pricing, this represents a solid middle ground—especially if you already own compatible CMMG magazines from previous builds. For traditional shooting disciplines, consider our Stevens 334 in .308 Win as a more conventional rifle platform.
Specs at a glance
Pros & cons
What works
- Radial delayed blowback reduces bolt carrier weight by approximately 22% compared to direct blowback systems
- TriggerTech single-stage trigger breaks at 3.5 pounds with minimal creep—far superior to standard mil-spec 6-8 pound pulls
- Optic-ready with full-length Picatinny rail accepts any micro or full-size red dot without adapter plates
- Left-side non-reciprocating charging handle clears optics and doesn't interfere with support hand position
Trade-offs
- Proprietary CMMG magazines cost $38 each versus $25 for standard Glock pattern magazines in competing platforms
- 4.7-pound unloaded weight is 0.8 pounds heavier than Sig MPX Copperhead—noticeable during extended training sessions
- No backup iron sights included—adds $90-150 for quality folding sights before practical use
- Linear compensator directs blast forward but increases overall length by 2.1 inches compared to flat muzzle device
Key attributes
| upc | 810103470088 |
| manufacturer | CMMG |
| manufacturer part number | 94A8041MB |
| action | Semi-Auto |
| barrel length | 10.50" |
| caliber/gauge | 9mm |
| capacity | 33 + 1 |
| safety | Ambidextrous |
| sights | Optic Ready |
Frequently asked questions
- Does this work with Glock magazines?
- No, it requires proprietary CMMG 9mm AR conversion magazines. These are modified Endomag inserts in standard AR-15 magazines, not compatible with Glock, Colt, or MP5 pattern mags. Each magazine costs approximately $35-40 from authorized dealers.
- Is it suppressor-ready?
- Yes, the 1/2x28 threaded barrel accepts standard 9mm suppressors. The 9.60-inch handguard has sufficient internal diameter to accommodate most suppressors up to 1.5 inches in diameter when using an appropriate muzzle device. I recommend checking suppressor alignment with a 0.358-inch gauge before first use.
- How long does shipping take to an FFL?
- We process and ship within 2 business days of cleared payment and FFL verification. Transit time via FedEx Ground is typically 3-5 business days continental US. FFLs in rural or remote locations may experience additional 1-2 day delays.
- Can I install my own AR-15 trigger?
- Yes, the Dissent MK4 uses standard AR-15 fire control groups. The installed TriggerTech is a single-stage adjustable model, but you can replace it with any mil-spec compatible trigger. I've successfully tested Geissele SSA-E and LaRue MBT-2S triggers without modification.
- Does it include a brace or stock?
- No, it ships with only a Picatinny rail adapter for attaching a pistol brace. The inclusion of any brace would create an NFA-regulated short-barreled rifle requiring a Form 1 tax stamp before installation. Consider SB Tactical's SBA3 or Maxim Defense's CQB stock (with proper registration) for optimal cheek weld.