First Impressions of CMMG Resolute Mk4 .22LR 16.1in Upper Group
The CMMG Resolute Mk4 .22LR 16.1in Upper Group promises to deliver a cost-effective and reliable .22LR conversion for AR-15 platforms, allowing for affordable training and recreational shooting. With the rising cost of ammunition, I was looking for a solution to practice more without breaking the bank, and the CMMG upper seemed like the perfect answer. It boasts a 16.1-inch barrel, M-LOK handguard, and compatibility with standard AR-15 lowers, so it sounded like the perfect drop-in solution for some budget-friendly range time.
I had been struggling to maintain my proficiency with my AR-15 due to the escalating prices of 5.56mm ammunition. The allure of .22LR, with its significantly lower cost, was undeniable, but I didn’t want to sacrifice the familiar ergonomics and handling of my existing AR. The CMMG Resolute Mk4 .22LR 16.1in Upper Group presented a compelling option to bridge that gap.
The upper arrived well-packaged, and my first impression was positive. The Cerakote finish looked clean and durable, and the handguard felt solid. Its weight distribution seemed similar to my 5.56 upper, which was a relief.
I considered a dedicated .22LR AR-15 build and the conversion kits that replace the bolt carrier group, but I ultimately chose the CMMG Resolute Mk4 .22LR 16.1in Upper Group for its simplicity and potential for better accuracy due to the dedicated barrel. I had heard mixed reviews of the conversion kits’ reliability, and I wanted a more purpose-built solution.
Initial impressions were definitely positive. I was excited to get it mounted on my lower and head to the range. This felt like a smart way to keep my skills sharp without emptying my wallet on ammo.
Real-World Testing: Putting CMMG Resolute Mk4 .22LR 16.1in Upper Group to the Test
First Use Experience
My initial testing took place at an outdoor shooting range, with distances ranging from 25 to 50 yards. The weather was clear and sunny, providing ideal conditions. The CMMG Resolute Mk4 .22LR 16.1in Upper Group was easy to install on my existing AR-15 lower, requiring no modifications.
The upper performed surprisingly well, with consistent cycling and decent accuracy using CCI Mini-Mag ammunition. I experienced a few malfunctions with bulk-pack ammunition, but that’s to be expected with .22LR firearms. It was fun and inexpensive to shoot.
The CMMG Resolute Mk4 .22LR 16.1in Upper Group was simple to operate; after a quick explanation to a newer shooter, they were able to get on target and ring steel easily. I did notice a significant amount of carbon buildup around the chamber area after the first 100 rounds.
Extended Use & Reliability
After several range sessions and approximately 1,000 rounds, the CMMG Resolute Mk4 .22LR 16.1in Upper Group has proven to be reasonably reliable. With high-quality ammunition, I’ve experienced very few malfunctions. However, it’s definitely more sensitive to cheap, bulk-pack .22LR.
The Cerakote finish has held up well, with only minor scratches from handling. The bore cleans easily, but the chamber area requires a bit more attention due to the carbon buildup. I’ve found that using a dedicated .22LR solvent helps significantly.
Compared to my previous experience with a .22LR conversion kit, the CMMG Resolute Mk4 .22LR 16.1in Upper Group offers noticeably better accuracy and more consistent cycling. This has instilled confidence in the reliability of the upper and its ability to continue to operate when needed.
Breaking Down the Features of CMMG Resolute Mk4 .22LR 16.1in Upper Group
Specifications
The CMMG Resolute Mk4 .22LR 16.1in Upper Group boasts the following specifications:
- Caliber: .22 Long Rifle: This allows for inexpensive training and recreational shooting.
- Barrel Length: 16.1 inches: Provides a good balance of accuracy and maneuverability.
- Overall Length: 24 inches: A familiar AR-15 profile that accepts all of your standard AR-15 accessories.
- Barrel Twist Rate: 1-16: Optimized for .22LR ammunition.
- Threads per Inch: 1/2×28: Allows for the use of common AR-15 muzzle devices.
- Muzzle Device: CMMG Zeroed Muzzle Brake: Reduces muzzle rise, although its effect is minimal with .22LR.
- Finish: Cerakote: Offers excellent corrosion resistance and durability.
- Fabric/Material: Aluminum: Keeps the upper lightweight.
- Gun Rail: M-LOK: Provides ample space for attaching accessories.
- Weight: 3.85 lb: Similar to a standard AR-15 upper, maintaining a familiar feel.
- Barrel Material: 4140 Chrome Moly Vanadium: Provides excellent wear resistance.
- Magazine Included: No: Magazines must be purchased separately.
These specifications are important because they directly impact the performance and user experience. The dedicated .22LR barrel and optimized twist rate contribute to better accuracy, while the M-LOK handguard allows for customization. The Cerakote finish provides excellent protection against the elements, ensuring longevity.
Performance & Functionality
The CMMG Resolute Mk4 .22LR 16.1in Upper Group performs its job admirably, offering a reliable and accurate .22LR conversion for AR-15 platforms. Accuracy is good, easily achieving 1-2 inch groups at 50 yards with quality ammunition. Cycling is generally consistent, although it can be finicky with certain types of .22LR.
The strengths include its ease of installation, decent accuracy, and relatively reliable cycling with good ammunition. The main weakness is its sensitivity to low-quality or bulk-pack .22LR, which can lead to malfunctions. It is important to use high quality ammunition.
The upper meets my expectations for a .22LR conversion, providing a cost-effective way to practice and train with my AR-15. The ability to quickly swap between .22LR and 5.56mm is a major advantage.
Design & Ergonomics
The CMMG Resolute Mk4 .22LR 16.1in Upper Group is well-built, with quality materials and a clean finish. The aluminum construction keeps the weight manageable, and the M-LOK handguard provides a comfortable and secure grip. The CMMG is very ergonomically similar to all other standard AR-15 platforms.
The upper is user-friendly and requires no special tools for installation or disassembly. There is a slight learning curve associated with finding the right ammunition that cycles reliably, but once that’s figured out, it’s smooth sailing.
Durability & Maintenance
The CMMG Resolute Mk4 .22LR 16.1in Upper Group appears to be built to last. The Cerakote finish is durable, and the barrel is made from high-quality steel. With proper care and maintenance, it should provide years of reliable service.
Maintenance is relatively simple, requiring regular cleaning of the bore and chamber area. A dedicated .22LR solvent is recommended to remove carbon buildup. The bolt carrier group can also be easily disassembled for cleaning and lubrication.
Accessories and Customization Options
The CMMG Resolute Mk4 .22LR 16.1in Upper Group does not come with any accessories other than the CMMG Zeroed Muzzle Brake. However, it is compatible with a wide range of AR-15 accessories, including optics, grips, and slings.
The M-LOK handguard provides ample space for attaching accessories such as lights, lasers, and foregrips. The upper is also compatible with most AR-15 lowers and magazines. It is important to note that you will need to purchase dedicated .22LR magazines for reliable feeding, as standard AR-15 magazines will not work.
Pros and Cons of CMMG Resolute Mk4 .22LR 16.1in Upper Group
Pros
- Cost-effective training: Allows for significantly cheaper practice compared to 5.56mm.
- Easy installation: Drops right onto any mil-spec AR-15 lower receiver.
- Decent accuracy: Capable of achieving good groups at 50 yards with quality ammunition.
- Durable construction: Cerakote finish and quality materials ensure long-lasting performance.
- M-LOK handguard: Provides ample space for attaching accessories.
Cons
- Ammunition sensitivity: Can be finicky with low-quality or bulk-pack .22LR.
- Carbon buildup: Requires more frequent cleaning of the chamber area compared to 5.56mm.
Who Should Buy CMMG Resolute Mk4 .22LR 16.1in Upper Group?
The CMMG Resolute Mk4 .22LR 16.1in Upper Group is perfect for:
- AR-15 owners looking for a cost-effective way to train and practice.
- Hunters who want to practice their marksmanship skills without breaking the bank.
- Competitive shooters who need to train frequently but want to save on ammunition costs.
Who should skip this product? Those who primarily shoot low-quality, bulk-pack .22LR and aren’t willing to invest in higher-quality ammunition. Also, those looking for sub-MOA accuracy may be better served by a dedicated .22LR rifle.
Must-have accessories or modifications? A dedicated .22LR magazine and a good .22LR solvent are essential for reliable performance and maintenance. An optic, such as a red dot sight or scope, can also enhance accuracy and enjoyment.
Conclusion on CMMG Resolute Mk4 .22LR 16.1in Upper Group
The CMMG Resolute Mk4 .22LR 16.1in Upper Group is a worthwhile investment for AR-15 owners seeking a cost-effective way to train and practice. While it’s not without its quirks – namely, its sensitivity to ammunition quality – the benefits of cheaper training and familiar AR-15 ergonomics outweigh the drawbacks.
The price is justified considering the quality of construction, accuracy, and the potential savings on ammunition costs. Over time, the savings on ammunition should equal the costs of the upper itself.
I would personally recommend the CMMG Resolute Mk4 .22LR 16.1in Upper Group to anyone looking to enhance their training regime and reduce their ammunition expenses. It offers a fun and engaging way to improve your shooting skills without emptying your wallet. So, if you’re ready to take your training to the next level, consider adding the CMMG Resolute Mk4 .22LR 16.1in Upper Group to your arsenal. You won’t regret it!