First Impressions of CMMG Bolt Carrier Group, Di, Dissent, Mk4
The CMMG Bolt Carrier Group, Di, Dissent, Mk4 promises a streamlined upgrade for anyone running a direct impingement DISSENT platform chambered in 5.56 or .300BLK. As someone who has spent years tweaking AR platforms, I am always looking for improvements in reliability and performance. The DISSENT system, with its unique operating system, requires specific components, so a dedicated BCG is crucial for smooth operation and optimal functionality.
I was drawn to this BCG because I’ve been experimenting with shorter-barreled AR builds in .300BLK for hog hunting and wanted a dedicated BCG. I’ve heard the DISSENT system can be finicky with standard AR-15 BCGs. The promise of a complete, purpose-built BCG from CMMG, a respected name in the AR world, seemed like a solid solution to potential reliability issues with my builds.
Upon unboxing, the CMMG Bolt Carrier Group, Di, Dissent, Mk4 feels robust and well-machined. The black finish is even and seems durable, suggesting it will hold up well to repeated use. My initial impression is positive, with the weight and feel instilling confidence in its quality.
I’ve previously used BCGs from Bravo Company Manufacturing (BCM) and Daniel Defense in my AR platforms. I chose the CMMG option due to its specific compatibility with the DISSENT system, which neither the BCM nor the DD BCGs are designed for. It was the specific application to the CMMG system that made this product more enticing.
Excited is an understatement; this BCG promises to bridge the reliability gap I’ve been trying to overcome with other parts. A properly functioning BCG is the heart of any AR; this upgrade is the opportunity to solve a problem I am happy to take.
Real-World Testing: Putting CMMG Bolt Carrier Group, Di, Dissent, Mk4 to the Test
First Use Experience
I tested the CMMG Bolt Carrier Group, Di, Dissent, Mk4 at my local shooting range on a custom-built 7.5-inch .300BLK DISSENT pistol. The conditions were fairly typical: sunny, around 70 degrees Fahrenheit, and relatively dry. I ran about 200 rounds of mixed ammunition, including both supersonic and subsonic loads.
The CMMG BCG performed flawlessly right out of the box. There were no failures to feed, extract, or eject, and the cycling felt smooth and consistent. The rifle was easy to control, and I am impressed with how reliable it has performed so far.
There were no initial issues or surprises; it simply worked as advertised. It gave me what I wanted: a properly functioning gun.
Extended Use & Reliability
After several months of regular use and roughly 1,000 rounds fired, the CMMG Bolt Carrier Group, Di, Dissent, Mk4 continues to impress. The finish shows minimal signs of wear, mostly around the contact points with the upper receiver. Cleaning and maintenance have been straightforward.
I’ve noticed no degradation in performance or reliability over time. The BCG still cycles smoothly and consistently, even after extended firing sessions. This CMMG BCG noticeably outperforms using a standard AR-15 BCG in my DISSENT pistol build.
Cleaning is a breeze, requiring only standard AR cleaning tools and solvents. This is what I expected, and so far, CMMG has not let me down.
Breaking Down the Features of CMMG Bolt Carrier Group, Di, Dissent, Mk4
Specifications
The CMMG Bolt Carrier Group, Di, Dissent, Mk4 is a complete BCG designed explicitly for direct impingement (DI) DISSENT firearms chambered in 5.56x45mm NATO or .300 AAC Blackout. The manufacturer is CMMG, and the BCG features a black finish for corrosion resistance. It is designed for right-handed firearms.
The specifications that stand out are its dedicated design for the DISSENT platform, ensuring proper gas system function, and its compatibility with both 5.56 and .300BLK calibers. The dedicated design ensures optimal performance, while the caliber compatibility adds versatility.
Performance & Functionality
The CMMG Bolt Carrier Group, Di, Dissent, Mk4 excels in its primary function: ensuring reliable cycling and consistent performance in a DISSENT platform. It provides a smooth and reliable operation, even with a wide range of ammunition. The ease of function exceeded my expectations.
The primary strength lies in its reliability and optimized design for the DISSENT system; however, it is limited to only the DISSENT platform and offers no benefits to standard AR-15 builds. The BCG delivers on its promise, however, future versions should have more options.
Design & Ergonomics
The CMMG Bolt Carrier Group, Di, Dissent, Mk4 is constructed from high-quality materials and features a durable black finish. The weight is consistent with standard AR-15 BCGs, and it feels solid and well-built. It has a quality feel and weight.
It’s designed for straightforward installation and use; there’s no learning curve for anyone familiar with AR-15 platforms. There is no fuss and is a drop-in part that works properly.
Durability & Maintenance
Given its robust construction and durable finish, the CMMG Bolt Carrier Group, Di, Dissent, Mk4 should provide a long service life with proper care. Routine cleaning and lubrication are all that’s needed to keep it running smoothly. The materials are high quality, and I see this product lasting a long time.
Disassembly for cleaning is identical to standard AR-15 BCGs, making maintenance simple and familiar. There are no proprietary parts or tools needed, making this easy to maintain.
Accessories and Customization Options
The CMMG Bolt Carrier Group, Di, Dissent, Mk4 is a complete unit and doesn’t require any additional accessories for basic function. Given its central role in the firearm’s operation, there are limited customization options beyond basic cleaning and lubrication products. It is what it is.
It is compatible with any DISSENT upper receiver that accepts a standard AR-15-style BCG. The broad DISSENT compatibility ensures it will work in a variety of configurations.
Pros and Cons of CMMG Bolt Carrier Group, Di, Dissent, Mk4
Pros
- Reliable cycling in DISSENT platforms. It functions properly and performs as expected.
- Compatibility with both 5.56 and .300BLK. One BCG, two caliber options.
- Durable construction and finish. High-quality materials for long life.
- Easy to install and maintain. No special tools or skills required.
- Complete BCG; no additional parts needed. Ready to go right out of the box.
Cons
- Limited to DISSENT platforms only; not compatible with standard AR-15s.
- Higher price point compared to generic AR-15 BCGs.
Who Should Buy CMMG Bolt Carrier Group, Di, Dissent, Mk4?
The CMMG Bolt Carrier Group, Di, Dissent, Mk4 is perfect for individuals who own or are building a CMMG DISSENT firearm in 5.56 or .300BLK. It is also good for those who want a reliable and dedicated BCG for their DISSENT platform. Anyone looking for simple AR upgrades will enjoy this product.
Anyone not running a CMMG DISSENT platform should skip this product. It is not compatible with standard AR-15s and offers no benefit over a standard BCG in those builds. No standard AR rifles should use this product.
A quality gun cleaning kit and lubricant are must-have accessories for maintaining the CMMG Bolt Carrier Group, Di, Dissent, Mk4. Other than that, it’s a complete unit and doesn’t require any modifications. Regular cleaning and maintenance are all that is needed.
Conclusion on CMMG Bolt Carrier Group, Di, Dissent, Mk4
The CMMG Bolt Carrier Group, Di, Dissent, Mk4 is a well-built and reliable BCG specifically designed for the CMMG DISSENT platform. It delivers on its promise of smooth cycling and consistent performance, especially in short-barreled configurations. The price is justified for those seeking a dedicated BCG for their DISSENT firearm.
I would personally recommend this BCG to anyone looking to optimize the performance of their CMMG DISSENT platform. It’s a worthwhile investment for enhanced reliability and peace of mind. If you value reliability and a drop-in product, this is for you.