First Impressions of CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine
The CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine represents a significant advancement in feeding the unique 5.7x28mm cartridge from the ubiquitous AR-15 platform. CMMG has redesigned this magazine with a focus on reliability and durability, addressing some common issues encountered with earlier generation conversions. Having spent over a decade working with various AR platforms and ammunition types, I was eager to see if this magazine could finally provide consistent performance with the 5.7x28mm round in an AR.
My interest in this magazine stemmed from the inherent appeal of the 5.7x28mm cartridge – its high velocity, flat trajectory, and relatively low recoil make it a potent round. Building a dedicated AR pistol chambered in 5.7x28mm, however, has always been plagued by magazine issues. This Gen 2 magazine promised to be the solution to the feeding problems that have haunted my previous attempts.
Upon receiving the magazine, the first thing I noticed was the updated aesthetic with its stylized texture grip and prominent 5.7x28mm engraving. The polymer felt robust and the overall construction appeared solid. Compared to the ProMag 5.7x28mm magazine and even older generation CMMG magazines, the improvements in the feed lips were immediately apparent.
I was cautiously optimistic, hoping this magazine would finally provide the reliable feeding necessary for serious use. My initial feeling was a blend of excitement and a touch of skepticism – years of unreliable 5.7 AR mags have made me hesitant to fully trust any new offering. It was time to put it through its paces.
Real-World Testing: Putting CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine to the Test
First Use Experience
My first outing with the CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine was at my local outdoor shooting range. I wanted to test it under controlled conditions, so I set up targets at various distances (25, 50, and 100 yards) and ran multiple drills. The weather was slightly overcast, but dry and about 70 degrees Fahrenheit.
Loading the magazine was straightforward, with no excessive spring tension or difficulty seating the rounds. During the first few magazines, I experienced zero malfunctions. This was a stark contrast to previous experiences with other 5.7 AR magazines, which often exhibited feeding issues from the start.
The only slight issue I noticed was that the magazine didn’t drop free every single time, sometimes needing a little assistance.
Extended Use & Reliability
After several weeks of consistent use, I can confidently say that the CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine has proven to be remarkably reliable. I’ve put several hundred rounds through it, and I have yet to experience a single failure to feed or double feed. The magazine body shows minimal signs of wear, with only minor scuff marks on the polymer.
Cleaning is simple, requiring only a quick wipe down with a cloth and occasional lubrication of the spring. It’s a vast improvement over previous 5.7 AR magazine experiences, where disassembly and meticulous cleaning were often necessary to maintain functionality. This magazine has outperformed every other 5.7x28mm AR magazine I’ve used to date in terms of reliability and durability.
Breaking Down the Features of CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine
Specifications
The CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine is designed specifically for AR-15 platforms chambered in 5.7x28mm. Its key specifications include a 32-round capacity, a polymer construction, and compatibility with standard AR-15 lower receivers when paired with a CMMG 5.7x28mm Radial Delayed Blowback upper. The magazine is black in color and weighs approximately 6.4 ounces empty.
These specifications are crucial for reliable performance. The 32-round capacity provides ample firepower, while the polymer construction ensures durability and reduces weight. Its AR-15 lower receiver compatibility allows for a seamless conversion without needing proprietary lowers.
Performance & Functionality
The primary function of this magazine is to reliably feed 5.7x28mm rounds into an AR-15. In this, the CMMG magazine excels. Its improved feed lip design and robust construction result in consistent feeding, even during rapid fire. It meets and exceeds expectations for a 5.7x28mm AR magazine, which historically have a bad reputation for unreliability.
The magazine’s strength lies in its reliable feeding, while a minor weakness is the occasional need for assistance to drop free. However, this doesn’t significantly detract from its overall performance.
Design & Ergonomics
The CMMG magazine features a user-friendly design with a stylized texture for enhanced grip. The polymer construction is robust yet lightweight, making it comfortable to handle and easy to load. There is a slight learning curve associated with proper loading technique to maximize reliability, however.
Durability & Maintenance
The high-quality polymer construction ensures that the CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine can withstand significant use and abuse. Regular cleaning and lubrication are recommended to maintain optimal performance. This magazine is built to last, with proper care and maintenance.
Accessories and Customization Options
The magazine itself doesn’t offer extensive customization options beyond aesthetic modifications like painting or applying grip tape. However, its compatibility with standard AR-15 lowers allows for a wide range of accessories. This includes aftermarket triggers, grips, and other components that enhance the overall shooting experience.
Pros and Cons of CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine
Pros
- Reliable Feeding: The redesigned feed lips ensure consistent feeding of 5.7x28mm rounds.
- High Capacity: 32-round capacity provides ample firepower for various applications.
- Durable Construction: High-quality polymer ensures long-lasting performance.
- AR-15 Compatibility: Works with standard AR-15 lowers when paired with a CMMG 5.7x28mm upper.
- Enhanced Grip: Stylized texture provides a secure and comfortable grip.
Cons
- Occasional drop-free issues: Magazines don’t always drop free without assistance.
- Price: At around $40, it’s more expensive than some other AR magazines.
Who Should Buy CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine?
The CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine is perfect for: individuals building or converting an AR-15 to the 5.7x28mm caliber and who require a high-capacity, reliable magazine. It is also ideal for competitive shooters or those engaging in tactical training scenarios that demand consistent performance.
Who should skip this product? Anyone not using a 5.7x28mm AR conversion.
A must-have accessory is a quality magazine loader to assist in quickly loading the 32-round capacity.
Conclusion on CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine
The CMMG MK4/AR-15 Gen 2 Series 5.7x28mm 32 Round Replacement Magazine is a game-changer for anyone running a 5.7x28mm AR-15. It addresses the historical reliability issues that have plagued other 5.7 magazines. The price is justified by its consistent performance, durability, and high capacity.
I would absolutely recommend this magazine to anyone looking for a dependable feeding solution for their 5.7x28mm AR-15. If you are building or already own a 5.7x28mm AR, do yourself a favor and invest in these magazines – you won’t regret it.