CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine Review

First Impressions of CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine

The CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine promises to deliver increased capacity and reliable feeding for 9mm AR platforms. With CMMG‘s reputation for quality and innovation in the AR world, this magazine immediately piqued my interest as a potential upgrade to my 9mm AR pistol setup. I was particularly drawn to the promise of cross-compatibility with existing 5.56 mag pouches, a feature that could simplify my gear organization considerably.

I’ve always been on the lookout for high-capacity magazines that don’t sacrifice reliability. Over the years, I have experienced enough malfunctions related to substandard magazines to heavily prioritize this key aspect of any firearm. The CMMG magazine was bought to solve the need for more rounds without constant reloads at the range and for increased capacity in a defensive scenario.

Upon receiving the magazine, my initial impression was positive. The polymer construction felt solid and durable, and the slightly extended length compared to a standard 5.56 mag seemed reasonable given the increased capacity. Compared to some cheaper aftermarket options I’ve tried in the past, the CMMG magazine immediately felt like a step up in quality.

Several other 9mm AR magazine options are on the market, most notably from Glock and Magpul. I specifically chose the CMMG magazine because it was designed to work seamlessly with CMMG‘s Radial Delayed Blowback system and utilize standard AR-15 magwells. I was hoping for a more integrated and reliable solution compared to using Glock magazine adapters.

Overall, my first impression was cautiously optimistic. The build quality seemed excellent, and the promise of increased capacity and reliable feeding was appealing. I was eager to put the CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine through its paces at the range and see how it performed under real-world conditions.

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Real-World Testing: Putting CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine to the Test

First Use Experience

I took the CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine to my local outdoor shooting range to test its performance with my 9mm AR pistol. The conditions were relatively mild, with a temperature around 70 degrees Fahrenheit and clear skies. I ran approximately 200 rounds of various 9mm ammunition types through the magazine, including 115-grain FMJ, 124-grain FMJ, and 147-grain JHP rounds.

The magazine loaded easily and locked positively into my AR-15 lower receiver. I experienced no initial feeding issues, and the rounds cycled smoothly. The magazine’s extended capacity was immediately noticeable, reducing the frequency of reloads and allowing me to focus more on my shooting.

However, after about 100 rounds, I began to experience occasional failures to feed. These malfunctions seemed to occur more frequently with the 147-grain JHP rounds. I also noticed that the magazine did not always drop freely from the magwell, requiring a slight tug to remove it.

Extended Use & Reliability

After several weeks of use and approximately 500 rounds fired, the CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine has shown both strengths and weaknesses. The magazine continues to load easily and generally feeds reliably with most types of 9mm ammunition. However, the failures to feed with 147-grain JHP rounds have persisted, and the magazine occasionally fails to lock the bolt back on the last round.

In terms of durability, the magazine shows minimal signs of wear and tear. The polymer construction has held up well to repeated use and handling. The exterior has some minor scratches.

Cleaning and maintenance are relatively straightforward. The magazine disassembles easily for cleaning, and the polymer body is resistant to most cleaning solvents. A simple wipe-down with a cloth and occasional lubrication of the spring are all that is required to keep the magazine in good working order.

Compared to other 9mm AR magazines I’ve used in the past, the CMMG magazine performs adequately. It offers a higher capacity than Glock magazines but does not achieve the same level of reliability I have experienced with some dedicated Glock-compatible AR lowers. The user feedback that the magazines only work with a CMMG upper and that they will feed on a milspec lower but not extract is very concerning.

Breaking Down the Features of CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine

Specifications

• Manufacturer: CMMG
• Magazine Capacity: 33 Rounds
• Caliber: 9mm Luger
• Gun Make: CMMG, AR Platform
• Gun Model: CMMG Mk4, AR-15
• Gun Type: Rifle
• Condition: New

These specifications are crucial for understanding the CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine‘s intended use and compatibility. The 33-round capacity provides a significant advantage in terms of firepower. The AR-15 platform compatibility allows it to be used in a wide range of firearms.

Performance & Functionality

The CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine generally performs well, offering a higher capacity than standard 9mm magazines. However, the occasional failures to feed and failure to lock the bolt back on the last round are significant drawbacks. The magazine’s primary strength is its increased capacity, which is beneficial for range use and defensive situations.

The main weakness is the magazine’s reliability issues, particularly with certain types of ammunition and its extraction issues with some lowers. While the CMMG magazine meets my basic expectations for a high-capacity 9mm magazine, the reliability issues prevent it from exceeding those expectations.

Design & Ergonomics

The CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine features a robust polymer construction that feels durable and well-made. Its exterior dimensions closely match those of common 5.56 AR15 magazines for cross-compatibility with existing mag pouches and carriers. The magazine is comfortable to handle and load.

The design is user-friendly, with a standard AR-15 magazine profile. There is a slight learning curve when initially loading the magazine to its full capacity, as the spring tension can be quite strong.

Durability & Maintenance

The CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine appears to be quite durable, with the polymer construction holding up well to repeated use and handling. I expect the magazine to last for many years with proper care and maintenance. Maintaining the magazine is straightforward, requiring only occasional cleaning and lubrication.

Accessories and Customization Options

The CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine does not come with any specific accessories. As a standard AR-15 magazine, it is compatible with a wide range of magazine pouches and carriers. There are no specific customization options for the magazine itself.

Pros and Cons of CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine

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Who Should Buy CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine?

The CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine is perfect for range shooters and those who prioritize higher capacity in their 9mm AR platforms. It is especially suitable for individuals using CMMG‘s Radial Delayed Blowback system, as it is designed to work seamlessly with that platform. This magazine is also good for those who want cross-compatibility with standard AR-15 mag pouches.

Those who should skip this product include individuals seeking maximum reliability with all types of 9mm ammunition, especially hollow points. Also, anyone with a non-CMMG upper receiver and AR-15 lower may experience issues and should avoid this product.

A must-have accessory for this magazine would be a reliable magazine loader to ease the process of filling the magazine to its full 33-round capacity.

Conclusion on CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine

The CMMG Mk4/Ar15 Gen 2, 9mm, 33 Round Pistol Magazine offers a compelling value proposition for those seeking increased capacity in their 9mm AR platforms. The $39.59 price point is reasonable, given the magazine’s durable construction and high capacity. However, the reliability issues, particularly with certain types of ammunition, are a significant concern.

While I appreciate the increased capacity and general reliability of the CMMG magazine, I cannot wholeheartedly recommend it due to the occasional failures to feed. The extraction issues with lowers other than CMMG brand are concerning and should be addressed. I would suggest potential buyers carefully consider their ammunition preferences and the specific AR-15 lower receiver they plan to use with this magazine. If you use a CMMG upper and want an OEM magazine then this is for you.