M*CARBO Brotherhood

Magazines Part 1: AR-9

Building an AR-9 results in a weapon that is extremely fun to shoot.
Very reliable and practical for various uses. And fairly cheap to shoot.
But, like all else, they need to be fed. This is the focus of this topic.

Basically there are three ways to do this. And all are good options.
You just need to decide which is best for you and your build.

First method is a dedicated lower receiver. This is the more pricey way.
Usually these lowers take either Glock or Colt style magazines.
There are other variations like the Quarter Circle 10 S226 that I have.
It allows me to feed my AR-9 pistol with Sig P226 mags.

The next two methods allow the use of standard lower receivers.

Second method is using adapter blocks. Priced between $60-100.
These are blocks that attach inside the magwell of the lower.
They allow the use of various 9MM pistol magazines.
I have no personal experience with these.

Third method is altering standard mags to feed 9MM cartridges.
This is the cheapest method of the three, to an extent.
It depends on the number of mags you choose to alter.
I recently built 3 PMags with Endomag inserts for my carbine.
I think I paid $75 for the inserts and uses mags that I already had.
With limited testing, these mags have been flawless so far.

Which ever method you choose, you will need mags.
So the cost of the mags should also be a consideration.

Something to keep in mind when buying a BCG for your build.
Some are designed to use either Glock or Colt style mags.
And some are designed to use both.

Thanks for reading. Have a great time. Be safe.


@ValorSolo Charles, so to use the Endomag inserts, I would just need an AR 9 upper with 9mm BCG and use the 5.56 lower I currently have?


these work and feed well with magpul I have not tried them on surplus.


these work well , as long as your 9, AR upper is cut for glock magazines

ive used these 2 in the past.


Correct. And a PMag gen M3, of course.


Slicker than snot on a new doorknob. And I’ve got plenty of 20 round PMags that aren’t getting used (almost hate to say it but the 10 rounders have become my go-to size). Ok, maybe I’ve got an AR-9 build in my future as well…


You’ll need the 30 rounders to use these inserts.
The Endomags come with a long limiter, that you cut down.
All the way from 10 rounds to 30. Cut it all off for 30.
Leave it intact for 10 rounds.


Thank you for this, missed that detail when reading the specs. Got a few 30s that aren’t seeing much action, still a consideration.


@ValorSolo Thanks Charles! I was not aware the Endomag insert existed. I have been thinking of an AR 9 build for a while, but did not want to have a dedicated lower and was not sure how the magwell inserts would work. This sounds like a great compromise.


found another option. Higher end. but supposedly top of the line.
ive heard the name before, but on the other end of the spec for my frankenAR’s fetish.


Hahn precision at $179. lot of juicy bits on this site…


Looks like that one is for Colt style mags only.
Pretty nice but a bit pricey.


LOL like iI said, out of my FrankenAR range, Battle arms even does a carbon fibre rail…


This makes method one a more affordable option.


they do a crystal clear, but dang it they dont do a 80% 9mm receiver …

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How about a grip that is a spare Glock mag holder?


I ordered one of these and it arrived today.
Here it is beside a standard size grip.
It’s freakin huge.


@ValorSolo Now if they’d just make them over-molded with a beaver tail…


Great price! I think I paid $120 for my blem (although I couldn’t tell what made it a blem) from New Frontier Armory.


My second outing with these was a complete failure.
Just wanted to share that. Not trying to dissuade you.
But really can’t recommend them either at this point.


@ValorSolo real word testing is always better hands on than magazines articles and hype brother. 'always.
why i always buy FN mags for the FN, HK mags for the HK, GLOCK mags for the SUB 2000. I venture out of norm only when i have to…


I don’t know. I’m going to do some maintenance on them, see if it’s fixable.
Maybe I’m overreacting. But the first mag I built ran 30 rounds flawlessly.
It was very dirty after those 30 rounds. I took it and another with me today.
Neither one worked very well, the dirty nor the never used one.