CMMG Mk4 .350 Legend Resolute Upper Group Receiver Review

First Impressions of CMMG Mk4 .350 Legend Resolute Upper Group Receiver

The CMMG Mk4 .350 Legend Resolute Upper Group Receiver arrives as a beacon of modern sporting rifle capability, chambered in the increasingly popular .350 Legend. CMMG is a well-respected name in the AR platform world, known for their innovative designs and commitment to quality, and this upper receiver group promises to deliver on both fronts. Hunters and target shooters alike are drawn to the .350 Legend for its straight-walled cartridge design that meets regulations in many states for deer hunting.

My journey to this upper receiver began with a need for a dedicated deer hunting AR-15 build compliant with those straight-walled cartridge restrictions in the Midwest. I was seeking a modern, accurate, and reliable upper receiver group that I could easily pair with a standard AR-15 lower. It needed to offer excellent performance in a hunting scenario.

Upon unboxing, the CMMG Mk4 .350 Legend Resolute Upper Group Receiver made a solid first impression. The fit and finish were excellent, with a clean, durable coating on the billet aluminum receiver. The handguard felt robust, offering a comfortable grip and ample M-LOK slots for accessories. Its weight felt balanced, not too heavy, suggesting good maneuverability in the field.

Compared to similar uppers from other manufacturers like Bear Creek Arsenal or Aero Precision (in other calibers for comparison’s sake), the CMMG stood out with its reputation for higher quality control and innovative features. While other options might be cheaper, I chose the CMMG for the peace of mind that comes with a well-established brand and a focus on reliability. I chose it for its reputation for precision.

Initially, I was excited and optimistic about the potential of the CMMG Mk4 .350 Legend Resolute Upper Group Receiver. It appeared to be a well-engineered and thoughtfully designed piece of equipment. I was eager to put it to the test and see if it lived up to its promise.

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Real-World Testing: Putting CMMG Mk4 .350 Legend Resolute Upper Group Receiver to the Test

First Use Experience

My initial testing of the CMMG Mk4 .350 Legend Resolute Upper Group Receiver took place at my local shooting range, followed by a weekend deer hunt in the dense forests of northern Wisconsin. The range provided a controlled environment to zero the optic and assess accuracy. The hunt offered a real-world challenge to its reliability and performance in a demanding scenario.

The CMMG performed admirably in both environments, displaying consistent accuracy and reliable cycling. We experienced light rain during the hunt, and the upper receiver showed no signs of malfunction or degradation in performance, proving its resistance to the elements. I was particularly impressed by the rifle’s intuitive handling and quick target acquisition.

The upper receiver required minimal adjustment to get accustomed to. The smooth action and comfortable ergonomics made it easy to operate, even with gloved hands during the hunt. The CMMG Zeroed Muzzle Brake effectively mitigated recoil, allowing for quick follow-up shots.

After the first use, I encountered no significant issues, only pleasant surprises. The accuracy was better than expected with standard factory ammunition. The reliable cycling instilled confidence in the platform.

Extended Use & Reliability

After several months of use, including multiple range trips and hunting excursions, the CMMG Mk4 .350 Legend Resolute Upper Group Receiver has proven to be a reliable and durable platform. I’ve fired several hundred rounds through it with only routine cleaning.

The finish has held up remarkably well, with no noticeable scratches or wear marks, even after being subjected to the rigors of the hunt. Regular cleaning and lubrication are easy. A quick wipe-down after each use keeps it in optimal condition.

Compared to previous experiences with budget-oriented AR uppers, the CMMG significantly outperforms them in terms of accuracy, reliability, and overall build quality. The CMMG Mk4 .350 Legend Resolute Upper Group Receiver instilled in me a level of confidence that I didn’t previously experience in an AR platform.

Breaking Down the Features of CMMG Mk4 .350 Legend Resolute Upper Group Receiver

Specifications

• Caliber: .350 Legend. This straight-walled cartridge is ideal for deer hunting in states with caliber restrictions, delivering significant energy on target with manageable recoil.

• Barrel Length: 16.1 inches. This length provides a good balance between maneuverability and ballistic performance, making it suitable for both hunting and target shooting.

• Barrel Profile: Medium Taper. The medium taper barrel offers a good balance between weight and rigidity, contributing to both accuracy and handling.

• Barrel Twist Rate: 1-10. This twist rate is optimized for stabilizing the .350 Legend projectile, ensuring consistent accuracy at various distances.

• Threads per Inch: 1/2×28. This standard thread pitch allows for the attachment of a wide variety of muzzle devices, including suppressors and compensators.

• Muzzle Device: CMMG Zeroed Muzzle Brake. This brake effectively reduces recoil and muzzle rise, allowing for faster follow-up shots and improved accuracy.

• Fabric/Material: Billet 6061 T6 Aluminum. The billet aluminum receiver is lightweight and durable, ensuring the upper can withstand the rigors of regular use.

• Handguard Length: 16.5 inches. This extended handguard provides ample space for mounting accessories and offers a comfortable gripping surface.

• Gun Rail: M-LOK. The M-LOK rail system allows for the easy attachment of accessories like lights, lasers, and foregrips, enhancing the rifle’s versatility.

• Weight: 3 lb. The lightweight design of the upper receiver contributes to the overall maneuverability of the rifle.

• Magazine Included: No. A magazine is not included, allowing the user to select their preferred magazine type and capacity.

• Mount Type: M-LOK. This reinforces the versatility, providing a secure and adaptable platform for accessories.

These specifications contribute to the overall performance and user experience by providing a well-balanced and accurate platform that is easy to handle and customize. The quality materials and thoughtful design ensure reliability and durability.

Performance & Functionality

The CMMG Mk4 .350 Legend Resolute Upper Group Receiver excels in its core function: delivering accurate and reliable performance with the .350 Legend cartridge. Accuracy with factory ammunition is consistently sub-MOA at 100 yards.

The upper receiver’s strengths lie in its smooth cycling, consistent accuracy, and manageable recoil. One potential weakness might be the lack of a included magazine.

The CMMG Mk4 .350 Legend Resolute Upper Group Receiver exceeded my expectations in terms of both accuracy and reliability. It has proven to be a capable platform for both target shooting and hunting.

Design & Ergonomics

The build quality of the CMMG Mk4 .350 Legend Resolute Upper Group Receiver is excellent, with a durable finish and tight tolerances. The 3lb weight feels balanced on a standard AR lower. The handguard offers a comfortable and secure grip.

The upper receiver is user-friendly, requiring minimal adjustment to get accustomed to. The controls are easy to access and operate.

Durability & Maintenance

The CMMG Mk4 .350 Legend Resolute Upper Group Receiver is built to last, with high-quality materials and a durable finish. With proper care and maintenance, it should provide years of reliable service.

Maintenance is straightforward, requiring only routine cleaning and lubrication. The design of the upper receiver allows for easy access to all critical components.

Accessories and Customization Options

The CMMG Mk4 .350 Legend Resolute Upper Group Receiver readily accepts a wide range of AR-15 accessories. The M-LOK handguard provides ample space for mounting lights, lasers, and foregrips.

The upper receiver is compatible with most standard AR-15 lowers, triggers, and stocks, allowing for extensive customization. It is designed to accept any AR-15 optic.

Pros and Cons of CMMG Mk4 .350 Legend Resolute Upper Group Receiver