The CMMG Resolute MK4 300 Blackout 16.10″, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform (No BCG or Charging Made a Bold First Impression
The CMMG Resolute MK4 300 Blackout 16.10″, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform (No BCG or Charging) arrives as a promise of precision and adaptability. CMMG has built a reputation for quality AR platform components, and this upper receiver group seemed a perfect starting point for a dedicated 300 Blackout build. Its sleek Midnight Bronze finish and M-LOK handguard hinted at a modern, capable platform.
My journey to this particular upper receiver group began with a desire to create a compact, yet effective, home defense and hog hunting AR pistol. I needed an upper that offered both reliability and the flexibility to mount various accessories. I was also drawn to the 300 Blackout caliber for its subsonic capabilities and effectiveness with suppressors.
The unboxing experience was straightforward. The upper was securely packaged. My initial impression was positive. The finish was flawless, and the weight felt balanced. The M-LOK handguard felt solid and provided ample space for customization.
Compared to similar offerings from Bravo Company Manufacturing (BCM) and Daniel Defense, the CMMG stood out for its unique aesthetics and competitive price point. While BCM and Daniel Defense are known for their unwavering reliability, the CMMG offered a similar feature set with a distinct visual appeal. Ultimately, the combination of aesthetics, features, and potential value swayed my decision.
My first impression was excitement tempered by a hint of apprehension, considering it lacked a BCG and charging handle. I was eager to mate it with a quality lower and see how it performed, but the absence of those essential components meant an additional investment and careful selection.
Real-World Testing: Putting CMMG Resolute MK4 300 Blackout 16.10″, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform (No BCG or Charging to the Test
First Use Experience
The CMMG Resolute MK4 300 Blackout upper was first tested at an indoor shooting range. This environment allowed for controlled conditions and precise zeroing. I paired it with a CMMG lower receiver, a quality bolt carrier group from Toolcraft, and a Radian Raptor charging handle.
The upper performed reliably with both supersonic and subsonic ammunition. There were no immediate issues with cycling or extraction. The M-LOK handguard remained secure. The balance of the complete rifle felt excellent.
After the first 50 rounds, I inspected the upper for any signs of premature wear or damage, but found none. There was a slight learning curve in terms of getting used to the recoil impulse of the 300 Blackout round in a lightweight platform. There were no malfunctions of any kind during the initial range session.
Extended Use & Reliability
After several months of use, the CMMG Resolute MK4 upper has proven to be remarkably durable. I’ve used it in various conditions, including temperatures ranging from 30 to 90 degrees Fahrenheit. I’ve also taken it through light rain with no impact on performance.
There are no significant signs of wear and tear on the finish or the handguard. Routine cleaning and lubrication are the only maintenance tasks I’ve performed. The bore cleans easily, and the upper continues to function flawlessly.
Compared to my previous experiences with budget-oriented AR uppers, the CMMG noticeably outperforms them in terms of accuracy and reliability. The consistency of the CMMG‘s performance is its defining characteristic.
Breaking Down the Features of CMMG Resolute MK4 300 Blackout 16.10″, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform (No BCG or Charging
Specifications
The CMMG Resolute MK4 300 Blackout upper features a 16.10-inch barrel chambered in 300 Blackout. The barrel is made from 4140 Chrome Moly Vanadium steel. It has a 1:7 twist rate. This twist rate is optimal for stabilizing both supersonic and subsonic 300 Blackout rounds.
The upper receiver is forged from 7075-T6 aluminum. It is finished in a durable Midnight Bronze Cerakote. The M-LOK free-float handguard is also made from aluminum. It provides ample space for mounting accessories.
The upper does not include a bolt carrier group (BCG) or charging handle. This allows the user to select components based on their specific needs and budget. The absence of these parts also contributes to the upper’s competitive price point.
The 16.10-inch barrel length is a sweet spot for the 300 Blackout cartridge, providing sufficient dwell time for complete powder burn while remaining relatively compact. The 1:7 twist rate ensures optimal stabilization for a wide range of bullet weights, from lightweight supersonics to heavy subsonic projectiles.
Performance & Functionality
The CMMG Resolute MK4 300 Blackout upper delivers excellent performance and reliable functionality. Accuracy is impressive with both supersonic and subsonic ammunition. With quality ammunition, sub-MOA groups are achievable.
The gas system is optimized for reliable cycling with a wide range of ammunition types. I’ve experienced no issues with short-stroking or failures to extract. The M-LOK handguard provides a stable and comfortable platform for attaching accessories such as optics, lights, and foregrips.
A potential weakness could be the absence of a forward assist. While unlikely to be needed with a properly maintained rifle, some users may prefer having this feature for added peace of mind. Overall, the CMMG meets and exceeds expectations for a mid-tier AR upper.
Design & Ergonomics
The CMMG Resolute MK4 boasts a well-thought-out design and comfortable ergonomics. The Midnight Bronze Cerakote finish provides a durable and aesthetically pleasing appearance. The M-LOK handguard is slim and lightweight, contributing to a balanced feel.
The upper receiver’s dimensions are within Mil-Spec tolerances. This ensures compatibility with a wide range of lower receivers and accessories. The lack of a charging handle and BCG allows for customization, but also adds an extra step for the end-user.
The rifle is user-friendly, even for those new to the AR platform. The only learning curve involves selecting and installing the necessary components (BCG and charging handle).
Durability & Maintenance
The CMMG Resolute MK4 appears to be built to last. The 7075-T6 aluminum upper receiver and durable Cerakote finish provide excellent resistance to wear and tear. The chrome-lined barrel is corrosion-resistant.
Maintenance is straightforward, requiring only routine cleaning and lubrication. The M-LOK handguard is easy to remove for access to the gas system and barrel. Based on my experience, this upper should provide years of reliable service with proper care.
Accessories and Customization Options
The CMMG Resolute MK4 upper offers a high degree of customization. The M-LOK handguard provides ample space for mounting accessories such as optics, lights, lasers, and foregrips. The upper is compatible with all Mil-Spec AR-15 lower receivers.
Due to the stripped-down nature of the upper (no BCG or charging handle), users can select these components based on their specific preferences. Popular upgrades include enhanced bolt carrier groups from companies like LMT and Geissele. Charging handle options are plentiful from companies like Radian and Strike Industries.
The modularity of the AR platform makes it easy to tailor the CMMG Resolute MK4 to individual needs. The ability to choose a preferred BCG and charging handle allows for a truly personalized rifle build.
Pros and Cons of CMMG Resolute MK4 300 Blackout 16.10″, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform (No BCG or Charging
Pros
- Excellent accuracy with both supersonic and subsonic ammunition.
- Durable construction and aesthetically pleasing Midnight Bronze Cerakote finish.
- M-LOK free-float handguard provides ample space for mounting accessories.
- Compatible with all Mil-Spec AR-15 lower receivers.
- Allows for customization of BCG and charging handle.
Cons
- Does not include a bolt carrier group (BCG) or charging handle.
- Lack of a forward assist may be a concern for some users.
Who Should Buy CMMG Resolute MK4 300 Blackout 16.10″, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform (No BCG or Charging?
The CMMG Resolute MK4 300 Blackout upper is perfect for experienced AR builders looking for a high-quality foundation for a 300 Blackout rifle or pistol. It is ideal for hog hunters, home defense enthusiasts, and those interested in suppressed shooting. The CMMG is suitable for those who appreciate a well-made upper receiver group that balances performance with aesthetics.
New AR builders might want to start with a complete upper receiver group that includes a BCG and charging handle. Users requiring a forward assist should consider other options. Those on a very tight budget may find the additional cost of the BCG and charging handle prohibitive.
A must-have accessory is a quality optic, such as a red dot sight or a low-power variable optic (LPVO). A suppressor is highly recommended to take full advantage of the 300 Blackout’s subsonic capabilities. A weapon light is essential for home defense applications.
Conclusion on CMMG Resolute MK4 300 Blackout 16.10″, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform (No BCG or Charging
The CMMG Resolute MK4 300 Blackout 16.10″, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform (No BCG or Charging) is a solid performer that offers a compelling combination of accuracy, durability, and customization options. CMMG has delivered a quality product that serves as an excellent starting point for a dedicated 300 Blackout build. The absence of a BCG and charging handle allows for personalization, but also adds to the overall cost.
The price is justified by the quality of the materials and construction. I would personally recommend this upper to anyone seeking a reliable and accurate 300 Blackout platform.
If you’re ready to embark on a 300 Blackout build, the CMMG Resolute MK4 is an excellent place to start. It’s time to experience the versatility and performance of this fantastic upper receiver group!