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) arrived, and I knew I had to build a new rifle around it. The promise of CMMG quality combined with the versatility of the 300 Blackout cartridge was an immediate draw.
My need for a dedicated 300 Blackout upper receiver arose from a desire to have a more specialized home defense and hog hunting platform. I wanted something compact yet capable of delivering significant stopping power in close quarters.
Unboxing the CMMG Resolute MK4 was a pleasant experience. The Midnight Bronze finish immediately caught my eye, a subtle yet striking departure from standard black. The M-LOK handguard felt solid and provided plenty of real estate for accessories.
I considered a similar upper from Bravo Company Manufacturing (BCM) and a complete upper from Daniel Defense. Ultimately, the CMMG offered a better balance of features, price, and aesthetics, plus the unique bronze finish sealed the deal. The BCM was a little too spartan, and the Daniel Defense was significantly more expensive.
My first impression was excitement; this wasn’t just another AR upper. The quality was apparent, and I envisioned the possibilities of building a compact, reliable, and visually appealing rifle.
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
I first took the completed rifle, built around the CMMG Resolute MK4 upper, to my local shooting range. The weather was typical Texas: hot and dusty.
The CMMG Resolute MK4 upper performed flawlessly, cycling both supersonic and subsonic rounds with ease. I experienced no malfunctions and was impressed by the consistent accuracy, even with different ammunition types. The rifle quickly became a favorite.
The M-LOK handguard was comfortable to grip and provided ample space for mounting accessories. The recoil was manageable, even with hotter supersonic loads.
My only initial surprise was how quickly the bronze finish heated up in the sun, requiring gloves after extended shooting sessions.
Extended Use & Reliability
After several months of regular use, the CMMG Resolute MK4 has proven to be incredibly reliable. I have fired hundreds of rounds through it, spanning various brands and grain weights of 300 Blackout ammunition.
The Midnight Bronze finish has held up remarkably well, showing minimal signs of wear despite being subjected to rough handling and occasional exposure to rain. Cleaning and maintenance have been straightforward, with the upper easily disassembled and reassembled.
Compared to my previous experience with a budget-friendly AR upper, the CMMG Resolute MK4 significantly outperforms it in terms of accuracy, reliability, and overall build quality. The difference is night and day.
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
- Caliber: 300 Blackout – A versatile cartridge known for its effectiveness in short-barreled rifles and suppressed applications.
- Barrel Length: 16.10″ – This barrel length provides a good balance of maneuverability and ballistic performance.
- Receiver Finish: Midnight Bronze – A durable and aesthetically pleasing Cerakote finish that offers enhanced corrosion resistance.
- Handguard: M-LOK Free-Float – Provides a rigid and customizable platform for mounting accessories.
- Compatibility: AR-Platform – Designed to seamlessly integrate with any standard AR-15 lower receiver.
- Note: BCG and Charging Handle Not Included – This allows the user to choose their preferred components.
These specifications are critical because they directly impact the performance and versatility of the upper receiver. The 300 Blackout caliber offers excellent terminal ballistics, while the 16.10″ barrel provides a reasonable balance between compact size and sufficient velocity. The M-LOK handguard allows for endless customization options for optics, lights, and other accessories.
Performance & Functionality
The CMMG Resolute MK4 performs its job exceptionally well. The accuracy is impressive, consistently delivering sub-MOA groups with quality ammunition.
Its reliability is unwavering, and it has cycled flawlessly through various 300 Blackout loads. The upper is also comfortable to shoot, with the free-float handguard providing a stable and ergonomic grip.
The only area that could be improved is the finish’s heat retention in direct sunlight. Other than that, the CMMG Resolute MK4 exceeds my expectations in every aspect.
Design & Ergonomics
The build quality of the CMMG Resolute MK4 is outstanding. The materials used are top-notch, and the fit and finish are impeccable.
The upper feels solid and well-balanced, inspiring confidence in its durability and longevity. The M-LOK handguard provides a comfortable and secure grip, even with gloves. There is no noticeable learning curve.
Durability & Maintenance
Based on my experience, the CMMG Resolute MK4 is built to last. The Midnight Bronze finish is incredibly durable, resisting scratches and wear even under demanding conditions.
Maintenance is simple and straightforward, requiring only basic cleaning and lubrication after each shooting session. The quality of the components ensures that repairs should be minimal.
Accessories and Customization Options
The CMMG Resolute MK4 readily accepts a wide range of accessories. The M-LOK handguard allows for the easy attachment of lights, lasers, grips, and other tactical accessories.
It’s also compatible with most AR-15 pattern optics and mounts. The ability to customize the upper to suit specific needs and preferences is a significant advantage.
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
- Exceptional Accuracy: Consistently delivers sub-MOA groups with quality ammunition.
- Unwavering Reliability: Cycles flawlessly through a wide range of 300 Blackout loads.
- Durable Finish: The Midnight Bronze Cerakote finish is highly resistant to scratches and wear.
- Versatile M-LOK Handguard: Provides ample space for mounting accessories and customizing the rifle.
- Easy Maintenance: Simple to disassemble, clean, and maintain.
Cons
- Finish Can Get Hot: The Midnight Bronze finish tends to get hot in direct sunlight.
- BCG & Charging Handle Not Included: Adds extra cost to the build.
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 is perfect for:
- Hog Hunters: The 300 Blackout cartridge is highly effective for taking down hogs.
- Home Defense Enthusiasts: The short-barreled configuration makes it ideal for close-quarters combat.
- AR-15 Builders: Offers a high-quality upper receiver for completing a custom AR build.
This product might not be ideal for:
- Budget-Conscious Shooters: There are cheaper options available, although they may sacrifice quality.
- Those Seeking a Complete Upper: The lack of a BCG and charging handle requires additional purchases.
A must-have accessory is a quality bolt carrier group (BCG). A premium charging handle is also recommended to enhance the overall user experience.
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 an outstanding upper receiver that delivers exceptional performance, reliability, and durability. The Midnight Bronze finish and M-LOK handguard add a touch of style and versatility.
The price is justified given the quality of the components and the overall build.
I would highly recommend the CMMG Resolute MK4 to anyone looking to build a high-quality 300 Blackout AR-15. Upgrade your AR build today and experience the CMMG difference!