CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver Review

First Thoughts on the CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver

The CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver represents a bold step in AR pistol design, and frankly, I’m intrigued. CMMG has taken a novel approach, ditching the traditional buffer tube and integrating the action directly into the upper receiver. This upper receiver promises increased maneuverability and reduced overall length, something many AR pistol builders crave, especially given the shifting legal landscape surrounding pistol braces.

My fascination with compact, potent platforms in 300 Blackout led me to explore the Dissent. I wanted a modular upper receiver that could provide impressive ballistics in a small package, without sacrificing the familiar AR-15 controls. Unboxing the Dissent, I immediately noted its solid construction and the unique left-side charging handle – a feature designed for speed and efficiency.

While several compact AR uppers exist, I was drawn to the CMMG Dissent’s bufferless design and delayed blowback system. Compared to a standard direct impingement system on a short barrel, the Dissent’s system should mitigate some of the excessive gas and recoil. My initial impression is excitement tempered with a healthy dose of skepticism; I’m eager to see if it lives up to the hype on the range.

Real-World Testing: Putting CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver to the Test

First Use Experience

My initial testing took place at an outdoor range, providing a safe and controlled environment to evaluate the Dissent’s performance. I mated the upper to a mil-spec AR-15 lower and tested it with a variety of 300 Blackout ammunition, both subsonic and supersonic. The weather was clear but cool, around 50 degrees Fahrenheit.

The side charging handle took a few magazines to get used to, but once I found my rhythm, it became surprisingly intuitive. The Dissent cycled reliably with both types of ammunition, though I observed slightly more felt recoil with supersonic rounds. There were no malfunctions in the first 100 rounds.

Extended Use & Reliability

After several range sessions spanning a few months, the CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver has proven to be impressively reliable. The Armor Black finish has held up well, with minimal signs of wear even after being transported in various range bags and cases. Cleaning is straightforward, though the delayed blowback system does seem to run cleaner than a standard DI system.

Compared to my experience with other short-barreled AR-15s in 300 Blackout, the Dissent offers a smoother shooting experience, thanks to the radial delayed blowback. The recoil impulse feels more manageable, especially with heavier subsonic rounds. Overall, I’m very pleased with the extended reliability and performance of the Dissent.

Breaking Down the Features of CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver

Specifications

The CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver is specifically designed for compact performance. Its key specifications include:

• Caliber: 300 Blackout, offering excellent subsonic performance and compatibility with AR-15 magazines.
• Barrel Length: 6.50 inches, a sweet spot for 300 Blackout, providing good velocity in a compact package.
• Twist Rate: 1:10″, optimized for stabilizing both subsonic and supersonic 300 Blackout projectiles.
• Barrel Finish: Black, providing corrosion resistance and a low-profile appearance.
• Receiver Finish: Armor Black, offering enhanced durability and scratch resistance.

These specifications are crucial because they contribute to the Dissent’s overall compactness, ballistic performance, and user experience. The 6.5″ barrel provides adequate dwell time for the 300 Blackout cartridge to achieve sufficient velocity while maintaining maneuverability. The radial delayed blowback system paired with these features make the Dissent a unique offering.

Performance & Functionality

The CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver performs exceptionally well in its intended role as a compact, reliable AR pistol upper. The radial delayed blowback system effectively reduces felt recoil and improves cycling reliability. The left-side charging handle allows for faster and more ergonomic bolt manipulation, especially for right-handed shooters.

The strengths lie in its compact size, reliable cycling, and manageable recoil. A weakness could be the learning curve associated with the side charging handle for those accustomed to traditional AR-15 configurations. The Dissent has exceeded my expectations for a bufferless AR upper in terms of reliability and shootability.

Design & Ergonomics

The build quality of the CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver is excellent, with tight tolerances and a durable Armor Black finish. The integrated action and bufferless design make it significantly shorter than a standard AR pistol. The left-side charging handle is well-positioned and easy to access.

The Dissent is relatively lightweight, contributing to its overall maneuverability. The design is user-friendly, although familiarization with the side charging handle is recommended for optimal performance.

Durability & Maintenance

The CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver appears to be built for long-term durability. The Armor Black finish provides excellent corrosion and scratch resistance. Maintenance is relatively simple, requiring standard AR-15 cleaning procedures.

Regular cleaning and lubrication of the bolt carrier group are recommended to ensure optimal performance. Given its robust construction, I expect the Dissent to provide years of reliable service.

Accessories and Customization Options

The CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver includes a 1913 Picatinny rail end plate, allowing for the attachment of various stocks or braces. The upper receiver is compatible with any standard AR-15 lower receiver. Optics can be easily mounted on the upper receiver’s Picatinny rail.

The Dissent is compatible with most AR-15 accessories, including triggers, grips, and magazines. The ability to easily customize the Dissent adds to its versatility and appeal.

Pros and Cons of CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver

Who Should Buy CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver?

The CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver is perfect for individuals seeking a compact and maneuverable AR pistol platform. This includes:

• AR pistol enthusiasts seeking a bufferless design.
• Home defense users needing a compact and potent firearm.
• Hunters wanting a lightweight and easily transportable 300 Blackout option.

Those who should skip this product include:

• Traditionalists who prefer the standard AR-15 buffer tube configuration.
• Shooters on a very tight budget, as the innovative design may command a higher price.

A must-have accessory would be a high-quality pistol brace or stock (depending on local regulations) to maximize stability and control. Also, a quality optic to take advantage of the accuracy potential.

Conclusion on CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver

The CMMG Dissent MK4 300 Blackout 6.50″, Left Side Charging Handle Upper Reciver is a well-engineered and innovative product that delivers on its promise of compactness and reliability. The radial delayed blowback system and left-side charging handle set it apart from traditional AR pistol uppers. While the price may be higher than some alternatives, the benefits of its design justify the cost for those seeking a premium, bufferless AR platform.

I would personally recommend the CMMG Dissent to anyone looking for a cutting-edge AR pistol upper receiver. Its compact size, reliable performance, and customizable design make it a standout choice in the 300 Blackout market. If you value maneuverability and innovation, the CMMG Dissent is worth the investment. Consider the CMMG Dissent if you want to experience the next evolution in AR pistol design!