[Review] Mean Arms EndoMag Conversion Kit
Want to shoot 9mm out of your AR-15 but don't want to get a completely new rifle? We review Mean Arms' EndoMag which turns your 5.56 lower into 9mm.
PRS/NRL22/Brutality/2-Gun Competitor. Career firearms writer. Former Boy Scout
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Pistol Caliber Carbines (PCCs) are all the rage right now and for good reason.
They're cheap to shoot, wicked fun, and great for training fundamental skills.
Buying a whole new rifle, while exciting, isn't always in the budget.
But converting your current rifle might be!
EndoMags from Mean Arms take a standard Magpul magazine and convert it from 5.56 NATO to 9mm allowing you to just change the upper on your standard AR-15 and BAM you're ready for some PCC plinking fun.
You should take a look at our video and if you liked it, don't forget to subscribe!
What Is The EndoMag?
This part is simple, really everything about it is simple, the Endo Mag is a conversion kit for standard Magpul magazines to turn them into 9mm mags.
Endo Mag has a great video on how to do the conversion, so we'll leave it to them to explain that part. From our end, the conversion is super easy, quick, and works great.
Once your magazine is converted, you just load it up with 9mm, and load it into the standard AR-15 mag well... And that's it really.
You'll need a new upper also and if you're looking for a budget option we highly recommend Palmetto State Armory 16" 9mm Complete Upper.
Mean Arms does recommend that you do a bit of break in so that your mags and BCG mesh well together. Personally, I didn't know about this step my first time and didn't have an issue - but on the other mags, we did the break in.
Restricted States May Apply
Normally anything fun on the firearms market is not available to those of us that live in less-free states, but Mean Arms actually took that into consideration when they made the EndoMag.
EndoMags ship with a 10-round limiter built into the assembly, but also make it very easy to cut that limiter down to 15-rounds or remove it granting you access to the full 30-rounds.
That's the kind of community I like to see in the firearms industry!
Range Report
Testing got cut a little short due to a sand storm that rolled in, but during the testing, we had literally zero problems. All three magazines worked with all 4 lowers and 3 different 9mm uppers in every possible configuration we could make.
Every combination of uppers and lowers we tried simply worked. Period.
That kind of flawless function is really rare to see with niche products like the EndoMag - props to Mean Arms!
Uppers Tested
Two different PSA 9mm uppers and 1 Franken upper made from a Rainier Upper and Lead Star Arms barrel.
It should be noted though that all of the testings was conducted on PSA Gen 4 Hybrid 9mm BCGs. EndoMags can be used with most 9mm BCGS, but there is some possibility that your mileage may vary.
Lowers Tested
Two lowers were from PSA rifles, one from Aero Precision, and the last was BCM.
Triggers included PSA Precision 2-Stage, BCM Stock Trigger, and a Rise Armament Super Sport.
None of the triggers presented an issue, all of them just ran perfectly.
Charging handles, safeties, and more all varied but none of those should present any change in reliability. We used standard carbine buffer weights and springs for all of the lowers, the same ones we use when the lower is shooting 5.56 NATO. And... there isn't much else to say, everything ran perfectly.
Who Is It For?
If you want to test out PCC shooting or you want to just try something new with your rifle or you really like your current lower and don't want to build a whole new one, EndoMags are perfect for you.
Personally, I really like them because they are just handy to have and use. I can keep a few PMAGs set up for 9mm, and then just switch uppers when the mood strikes.
What might be best of all is that this is a very economical way of getting into the PCC world. A new upper will run around $300 or less, the EndoMags are roughly $30 each, plus $12 PAMGs. For under $350 you can build yourself a PCC using your normal AR-15 lower.
Bang for your buck, that is a steal of a deal!
Cons?
I didn't have any. Weird, I know, but I just didn't have any issues with it. Everything worked perfectly. The mags were easy to install, easy to load, easy to use. My rifle never failed and I had a blast.
There are three things that you should keep in mind.
The Trigger
One of the flaws with any 9mm blowback AR system is that they are inherently rougher on triggers than 5.56 NATO is. Madness, I know, but it's true.
The direct blowback action of 9mm uppers means a harder impact on the hammer and more energy transmitted into the trigger pack. This can cause pins to walk or parts to break.
BUT this really isn't an issue for most triggers, normally it's the higher-end race triggers that are finely tuned that run into this issue... We know because we've broken a trigger before on another 9mm set up!
That said, any PCC rated trigger won't have this issue. And most mil-spec or duty triggers won't either. But if you have a real nice 3-gun trigger in your lower, you might want to check with the manufacturer before throwing a 9mm upper on it.
Clearing Your Rifle
Not so much a con as just a quirk of design. Because the EndoMag acts as its own ejector, you need to leave the magazine in to extract and eject a round from the chamber.
If you want to do this with rounds still in the magazine, you need to rack your charging handle back, press your bolt hold up to lock your bolt, release the magazine, and then close the bolt.
If you just want to clear the rifle at the end of shooting, you need an empty EndoMag in the magwell to do so.
Otherwise, you might extract a round and rechamber the round without ever ejecting it.
The Looks
Part of the fun of a PCC is the look of a PCC, and this can't be ignored. A big 'ol Glock mag sticking out of a AR-9 lower just looks awesome and is fun. That isn't something you get with the EndoMag.
Is that a con?
Kind of? It's something to consider, and something to consider is that this might be a gateway gun. Once you find out how awesome a PCC is, you'll be building yourself a lower soon after!
By The Numbers
Accuracy: 5/5
Accuracy was unaffected by the EndoMag, so as long as your upper is accurate you're good to go.
Installation: 5/5
It really is super simple. As long as you've taken a magazine apart before, nothing will be new to you.
Looks: 2/5
It takes away from that awesome AR-9 vibe we love about PCCs, but that's the price you pay for using a cool conversion.
Customization: 5/5
Since this is the customization, the sky is the limit. Lowers, triggers, uppers, barrels, optics, if you can do it to an AR-15 you can do it to an AR-15 loaded with EndoMags!
Bang For Your Buck: 5/5
Hands down the cheapest way of getting into the PCC world. Awesome.
Overall Rating: 4/5
Parting Shots
Is the EndoMag for everyone? Yes and no. If you want to go deep into PCCs, then you might want a dedicated lower. But if this is a plinker, training aid, or just trying something new - then it makes a lot of sense.
And it's just so fun!
All said and done, I really like the EndoMag. It was reliable, fun, and great to use. I'll be picking up some more soon.
What is your PCC set up? 9mm, .40 S&W, or .45 ACP? Let us know in the comments! If you think you want to jump into the deep end, read about the Best Pistol Caliber Carbines!
