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AR-9 ENDOMAGS 9MM CONVERSION KIT Reviews & Ratings

Several companies have developed 9mm conversion systems designed for use in standard AR-15 lowers and uppers. However, feeding a 9mm magazine through a standard AR-15 magazine well presents some issues. Typically, this has been solved by the use of magwell inserts, but Mean Arms tackled the issue with a different take: why not change the magazine itself? The Mean Arms AR-9 Endomag Conversion Kit takes any standard Gen 2 or Gen 3 Magpul PMAG and allows it to be converted to feed 9mm rounds. The conversion is built for use with Glock®or Colt 9mm bolt-carrier groups. The kit comes ready to convert 10-round magazines, but it can be modified to fit 20- or 30-round magazines. No magwell adapter is needed for use with the Mean Arms AR-9 Endomag Conversion Kit, and the company ensures reliable performance with all brands of 9mm ammo.

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3 Stars

2 Stars

1 Stars

22%

Reviews Summary

The AR-9 Endomags conversion kit has sparked mixed reviews, with many users praising its affordability, versatility, and effective design on compatible builds. However, notable reliability issues, specifically jams and feeding problems, plagued several users, often linked to its plastic ejector. Overall, it offers potential but may require careful setup and adjustments for optimal performance.

What Reviewers Are Saying

Reliability and Performance

45%

A significant number of reviewers expressed frustration with the Endomags' reliability, reporting frequent jams and difficulties in feeding rounds. While some users experienced flawless operation, these issues were prominently noted, indicating that proper setup and compatible parts are crucial for consistent performance.

Ease of Use and Installation

60%

Many customers appreciated the straightforward installation process, finding the conversion kit simple to integrate into their existing setups. The ability to use standard PMAGs for a 9mm setup was also seen as a major advantage, adding to its practicality for builders on a budget.

Design Concerns

35%

Several users raised concerns about the materials used in the ejector, describing it as flimsy. This aspect has led to worries about the long-term durability of the product. While some were satisfied with its performance, others felt that a sturdier ejector could improve reliability.

Value for Money

55%

Overall, reviewers found the Endomags to be an economically friendly option, particularly for those looking to convert existing AR-15 lowers to 9mm. Consumers noted that the price point saves money compared to purchasing proprietary magazines, reaching a good compromise between cost and functionality.

Satisfaction with Adaptability

50%

Users highlighted the convenience of the Endomags in terms of adaptability, allowing for easy switching between calibers without the need for extensive modifications. This feature appealed to builders who want flexibility in their firearm configurations.

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I would go with the EXOMAG if I had to do it over, but these worked fine.

Built 9mm 16" upper. Used in 3, Mag Gen 2 old mags I had around. Flawless.

Would you recommend this? Yes, I would recommend to a friend

by WALTER J. on July 23, 2026

Verified Purchase

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Works well up to a point

I bought a couple of these for use with an FM9 upper and generic lower. Very easy to assemble and they've run flawlessly for me. Bonus points for fitting snugly in mag pouches and gun bags that are set up for AR-15s. My main complaint is that it's very difficult to load more than 20 rounds. When you are loading, it's very easy to put pressure on and bend the ejector, which worries me that I'll break it off. I was also concerned about high bolt velocity wearing down the polymer ejector, but switching to FM's buffer and spring set helped a lot.

Endomag Feels "Flimsy" but it Works

Since I had a new Magpul gen.3 P-mag laying around, I decided to order the Mean Arms 9mm conversion insert from Brownells. The unit felt rather flimsy (the plastic ejector in particular), but it fit fine in my P-mag. I inserted the mag in a mil-spec AR lower mated to an FM 9mm upper, and followed the Mean Arms recommended break-in procedure in the company's video. Everything went well, and I fired 50 rounds of various 9mm 115fmj rounds through the set-up with no problems. The bolt locked back on an empty mag. The only reason I'm giving the unit 4 stars instead of 5 is that I'm concerned about the ejector's long term prospects. However, Mean Arms specifies a lifetime replacement guaranty on their website. If you want a cheap, quick and easily reversible 9mm conversion option for your standard AR lower, I do recommend the Mean Arms Endomag.