CMMG Dissent BR4 30A650ACT 300 AAC Blackout 16.10in 10+1
Pros & cons
What works
- 16.10-inch barrel maintains non-NFA compliance—avoids 9-12 month SBR tax stamp wait
- Radial-delay blowback system reduces felt recoil by approximately 30% compared to direct impingement
- Full-length 13.5-inch M-LOK handguard provides uninterrupted accessory mounting surface
- Coyote Tan Cerakote finish adds corrosion resistance rated for 500+ hours of salt spray testing
Trade-offs
- Proprietary bolt carrier group limits aftermarket options—replacement costs $289 vs $150 for standard AR-15 BCG
- No iron sights included—requires immediate optics purchase adding $150-$800 to total cost
- 300 Blackout ammunition averages $0.85/round for supersonic—78% more expensive than 5.56 NATO
Video review
Expert review
Specs at a glance
About this product
What is the CMMG Dissent BR4 30A650ACT 300 AAC Blackout 16.10in 10+1?
The CMMG Dissent BR4 30A650ACT is a purpose-built 300 Blackout carbine designed for shooters who require NFA compliance without sacrificing ballistics. This configuration uses a 16.10-inch barrel specifically to avoid the ATF Form 1 and Form 4 paperwork required for SBRs, maintaining a 38.10-inch overall length that sidesteps federal short-barreled rifle classifications. The rifle achieves a foundational weight of 7.80 pounds unloaded, balancing stability for precision work with manageable handling for field use.
What is the CMMG Dissent BR4 used for?
The CMMG Dissent BR4 is used for high-accuracy medium-game hunting and defensive applications where subsonic ammunition and suppressors are preferred. Its 1:7 twist rate barrel stabilizes heavy 220-grain subsonic rounds that remain under the 1,100 feet per second sound barrier, creating an ideal platform for suppressed shooting. The full-length Picatinny rail and zeroed single-stage trigger provide the mounting surface and pull consistency needed for optics and precision shots at distances up to 200 yards.
How does the CMMG Dissent BR4 compare to the Stevens 334 Rifle?
The CMMG Dissent BR4 is a semi-automatic caliber-specific platform, while the Stevens 334 Rifle is a bolt-action multi-caliber system. The Dissent offers faster follow-up shots and modular accessory mounting via its 13.5-inch M-LOK handguard, compared to the Stevens' traditional 20-inch barrel and fixed synthetic stock. For hunters prioritizing rapid target re-engagement with a suppressor, the Dissent is superior; for those seeking maximum long-range accuracy with a single shot, the Stevens 334 in .308 Winchester holds the advantage.
What does it weigh and what are the dimensions?
The CMMG Dissent BR4 weighs 7.80 pounds (3.54 kg) with an empty magazine and measures 38.10 inches (968 mm) from muzzle to stock. The critical barrel length is 16.10 inches (409 mm) with a 5/8x24 thread pitch, while the handguard provides 13.5 inches (343 mm) of continuous accessory rail. This specific dimensional profile keeps the rifle 2.1 inches over the federal SBR threshold, a deliberate compliance margin that avoids a 9-12 month Form 1 wait.
Who is this NOT for?
This rifle is not for budget-first shooters or those seeking a general-purpose 5.56 NATO platform. The 300 Blackout cartridge costs approximately $0.85 per round for supersonic range ammo, nearly double the cost of comparable 5.56. Furthermore, newcomers to the NFA process should consider a platform like the Stevens 334 in .243 Win which avoids suppressor paperwork entirely, whereas the Dissent practically demands a Form 4 tax stamp to realize its ballistic potential.
What's in the box?
The rifle ships with two Magpul 10-round PMAGs, a CMMG Zeroed Muzzle Brake installed to 30 ft-lbs of torque, and a standard sling attachment point. Documentation includes ATF-compliant owner's manuals and a warranty card valid for 36 months from the purchase date. Notably absent are any optics, suppressor adapters, or cleaning kits—expect to invest an additional $400-$2000 in a quality LPVO optic and compatible muzzle device for proper function.
Is the CMMG Dissent BR4 worth it at $1943.99?
At $1943.99, the CMMG Dissent BR4 justifies its cost for shooters already committed to the 300 Blackout ecosystem who require a compliant non-NFA host. The price includes the Coyote Tan Cerakote finish ($150 value), the zeroed single-stage trigger ($80 value), and the Magpul SGA stock system ($100 value) over a basic mil-spec build. For comparison, building a similar rifle from stripped receivers and aftermarket parts would cost approximately $1650 before accounting for the 8-10 hours of assembly and headspace verification by a qualified gunsmith.
Key attributes
| upc | 840442500306 |
| manufacturer | CMMG |
| manufacturer part number | 30A650ACT |
| barrel length | 16.10" |
| caliber/gauge | .300 AAC Blackout |
| capacity | 10 + 1 |
| safety | Crossbolt |
Frequently asked questions
- Is it compatible with standard AR-15 parts?
- The upper and lower receivers use a proprietary radial-delay blowback system that is not compatible with standard AR-15 bolt carrier groups or buffers. However, it accepts Mil-Spec AR-15 fire control groups, pistol grips, and stocks like the included Magpul SGA. For barrel and handguard swaps, you must use CMMG's specific barrel extension pattern which differs from a standard AR-15.
- Does this work with a SilencerCo Omega 300 suppressor?
- Yes, with the correct muzzle device. The 16.10-inch barrel has 5/8x24 threads compatible with SilencerCo's ASR muzzle brake or direct-thread adapter. You must first remove the factory-installed CMMG Zeroed Muzzle Brake, which requires a 3/4-inch armorer's wrench and proper vise block to avoid damaging the 0.750-inch journal diameter. Always verify suppressor alignment with alignment rods before live firing.
- How long does shipping take to an FFL?
- Ironclad Armory processes orders within 2 business days and ships via UPS or FedEx with 3-5 business day transit time to your selected FFL dealer. The entire process typically completes in 7-10 business days from order to FFL notification. You must contact your FFL dealer in advance to provide their license and coordinate pickup—some dealers charge a $25-$50 transfer fee upon receipt.
- Can I return it if I don't like the trigger pull?
- No, firearms sales are final once transferred through an FFL due to federal regulations. The zeroed single-stage trigger has a factory-set pull weight of 4.5-5.5 pounds which is not adjustable without aftermarket springs. If the trigger doesn't meet your needs, you can replace it with any Mil-Spec AR-15 trigger group, but the rifle itself cannot be returned for refund or exchange after the 4473 form is completed.