9mm AR uppers - what are my options?

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Jan 20, 2003
So... I'm thinking about building a 9mm AR-15. I realize that it's not as powerful as a 5.56, but I think it would be a fun plinking rifle with some potential for home defense.
Who is building decent 9mm uppers? What kind of magazines do they take? And what parts will I need to convert the lower to work with a smaller magazine?
One thing to consider is the cost. A 9mm upper setup will likely cost around $500-$700. 9mm ammo is currently available for around 30 cents per round. So you have an upper the price of a decent AK and 9mm is more expensive than 7.62x39 or 5.45x39 (which can be had for between 16-26 cents per round). I have a 9mm carbine, but it doesnt get much use due to the fact that I just cant justify spending more on gravel pit quality 9mm ammo when my AK's are cheaper to feed. It just doesnt make much sense.:uhoh: Thats why 9mm uppers aren't more popular, why buy an upper when you can get a good complete carbine/rifle for the same price?
Suppressed 9mm carbines with 147gr ammo is a lot of fun. Much more so than an AK, imvho.

The uppers are either Olympic style or Colt/Rock River style.


You can use a mag block for uzi style magazines or you can go with a dedicated lower.

The dedicated lowers don't require blocks, but can't be used for anything but 9mm either.

When it comes to dedicated lowers, you can use Colt style magazines (modified uzi mags) or some use GLOCK style magazines.

UZI modified mags: Rock River, DDLES

For the Glock Style magazines, DDLES makes the best one out there. Lone Wolf makes one as well, but the DDLES one is superior.

If you are going to go with a Glock Mag lower, then you'll need to mill the Colt Style bolt narrow to fit between the single feed magazine. It's easy to do, and you can get it done at ADCO Firearms, if you're interested.


Traditionally, they made an AR that uses STEN magazines. They have their own barrel design, bolt design, and extractor assembly on the upper of their firearms. They were the first to use GLOCK mags for feeding their AR's as well. If you can find one, they are solid performers. But their proprietary parts may be a turn off for some.

The current offerings from Olympic have their own proprietary magazines, and they were making a few glock style rifles late last year or earlier this year.

Decide on which magazine you want to use and we can help you narrow it down some more.

Good Luck.
Ah.... after thinking the cost over, maybe it doesn't make sense. I hadn't realized that a decent 9mm upper would run the cost as a whole PSA rifle. Taken in that context, for something that's probably just going to be fun plinker, it's probably more rational to invest in a 5.56 rifle. Seems like it would have a wider resale market if I ever wanted to sell it too.
Ah.... after thinking the cost over, maybe it doesn't make sense. I hadn't realized that a decent 9mm upper would run the cost as a whole PSA rifle. Taken in that context, for something that's probably just going to be fun plinker, it's probably more rational to invest in a 5.56 rifle

It's hard to beat the value of a 5.56mm PSA rifle.

Another great option for centerfire plinking would be a 7.62x39mm O-PAP (Yugo M70 AK). They are excellent rifles that are now available for under $600, and 7.62x39mm steel-cased ammo is still a good bit cheaper than 5.56mm/.223.
I will say that shooting a 9mm out of a rifle was fun the few times I did it. A lot less blast and intensity than a 5.56 or 7.62x39. I'm not sure if that works out to be cost effective in my case but I guess it doesn't hurt to hear some more ideas.
I just did this, this summer and it's actually kind of complicated at first. Took me awhile to figure out what to do. In the end it is a tack driver up to 50 yards and allot of fun. I reload, so 9mm runs me 9 cents. Looking to put in for a suppressor in a few weeks and i imagine that will be awesome! If no one else chimes in I'll write you something up when i get home. Too much too type on a phone. One question are either of you who are interested looking for a dedicated 9mm lower or a 223 lower that you can convert back and forth? I did the second option, myself.
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If I do it, I'll be wanting to go with a .223 lower that can be converted back. The beauty of the AR is that you can switch it to what you're interested in at the time. So I'll be sticking with that because it gives the most versatility.

BTW - I can also load 9mm. That's why I was thinking about a 9mm upper.
I have always fancied the lone wolff AR that uses glock mags.

http://www.lonewolfdist.com/Detail.aspx?PROD=285845 $400 lower
http://www.lonewolfdist.com/Detail.aspx?PROD=187826&CAT=2895 $700 upper

I shot an uzi 9mm carbine at the range friday, and it was great. no recoil to speak of, far quieter and far less muzzle blast than a 556 ar, and if you were to screw a 9mm can on the end.......yum!

I will end up doing a 300 aac instead because I already have the lower, but that 9mm sure is tempting.
greyling22 said:
I have always fancied the lone wolff AR that uses glock mags.

The DDLES Lower that uses Glock Mags is nicer. I've run both, and the DDLES is better.
Alright, Goon. Here it goes: RJrivero gave a great start, olympic arms is one way to go but I couldn't even find one available and wanted something with a last round hold open. Plus they do seem to be pricier and as RJ said proprietary parts.

The following deals with a standard AR-15 lower that you want to make interchangeable. If you go with a dedicated lower then pick a glock compatible lower and buy block mags, Done and done.

You will need a complete AR-15 lower with all parts installed, then you need a magwell block or magwell adapter this allows certain magazines to fit into the magwell of your gun and lock in place. There are a number of good options include a Rock River Arms (I have this one), Spikes tactical and Hahn precision are the top of the line. I'd of preferred spikes but couldn't find it at the time. I believe all three of these have a last round bolt hold open feature if the magazine you are using also has the feature. Normally, you will adjust the height of the magwell block a little bit up and down if your having any feeding or ejection issues, the spikes tactical gives the most adjustment but for the most part they should all be plug and play. Most have a screw on the bottom that you tighten to lock it into the magwell tightly. This allows you to use your mag release button without pulling the magwell block out too.
~ There are two types of magwell adaptor, one's that go into the magwell from the bottom where you put your magazine in and ones that go from the top of the lower but require removal of the bolt release mechanism to install. The last option is generally used on a dedicated lower that you do not plan on changing back and forth.

Next you need magazines that fit that magwell block, The best are Colt 9mm ar style mags like these: http://www.brownells.com/magazines/...15-m16-9mm-colt-style-magazine-prod38850.aspx
There are many makers of these style of magazines but I've found that metalform works the best for me. Real genuine colt ar 9mm mags are very expensive. Promag versions are cheap and that's about it, they are cheap. I tried one and it is too tight for my block and I've heard of the plastic versions splitting at the seam when full. The advantage of these are that they feature a last round hold open (which I wanted, no exceptions).
~It is also possible to use a Modified Uzi magazine which simply means that the hole to lock the magazine in place in the magwell has been redrilled in the magazine body to be higher up but it will NOT hold the bolt back even on a magwell block that has that feature.

Pretty straight forward really, you pick an upper you like and go with it. But be aware that the bolt it includes will make a difference, read the next section for explanation. Personally, I have and like my CMMG 9mm upper. YHM, RRA, CMMG, and Spikes Tactical all make uppers. I'm sure there are others I've forgotten, so maybe others will chime in there. Possibly worth noting, my CMMG upper uses a 1/2 x 36 threaded barrel, as I want to buy a suppressor it is a little odd and inconvenient so you may pay attention to that.

There are two types of bolts when building a 9mm AR, one that is ramped and one that is not. The bottom of the bolt nearest the portion where the hammer hits the bolt has a portion of about 1 inch cut out of the slide making it a ramp rather than flat the whole way. The ramping is to allow for more travel of the bolt before the hammer is reset as opposed to a non-ramped bolt that slams the hammer back too fast leading to problems. A bolt that is ramped will allow you to use your standard AR or M16 hammer. To my knowledge RRA does NOT use a ramped bolt but recommends a 9mm hammer or pay to have the bolt ramped.
It looks like this:

I'm under the impression that you cannot use this hammer on a 223 so I avoided the whole problem and bought a CMMG ramped bolt and kept my original hammer. This is the way the Colt 9mm AR was designed as opposed to the RRA 9mm AR which uses the non-ramped bolt and special hammer. As I stated I went with the Colt style.

This one I haven't figured out completely, I bought a Spikes tactical combo buffer for my AR, This:
Your supposed to use the actual buffer like any other buffer and it can safely be used on 9mm and 223, the extra little part is the buffer spacer and is supposed to go on the other end of the buffer spring to add a little tension to the spring to keep the bolt closed a little longer. I have done both ways, with and without the extra piece when shooting 9mm and I have noticed NO difference at all, I do like the spikes buffer though, very smooth in the 223 configuration. So it's up to you, I can't see any harm in using your stock buffer at this point.

To Put It All Together, in it's simplest configuration:
9mm upper of your choice with a ramped bolt, Magwell block and compatible magazine, Done! Go shoot and have fun!

The last thing I can think of is a website that you could use to buy some of your equipment. I bought a magazine from them and they were very good and fast shipping. http://stores.9mmar.com/StoreFront.bok

Good Luck, Hopefully I cleared up things a bit!


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I have a DDLES lower that accepts Colt style magazines and a RRA upper integrally suppressed by SRT Arms. Awesome combination. The DDLES lowers are amazing. The craftsmanship and quality on them in unmmatched. And the mag well is made for the skinnier 9mm magazine. I always thought the 9mm ARs with .223 magwells looked kind of quirky.
Hyrulejedi86 summed that up pretty good. But I'll throw in a couple cents worth anyway.

First, the 9mm upper isn't cheap no matter how you look at it. The magwell adapter is expensive for a good one, and that is kind of a "hidden" cost. You can get a ProMag adapter for cheap but it may or may not work for you. It requires a top load installation as mentioned and that really kills the rapid changeover from 9mm to .223.

I've tried a sorts of mags and the last round bolt hold open is a must have feature for me as well. The only magazine that feeds and locks for me every single time is the Promag polymer mag, which is counter to what almost everyone else says. It's a nice bonus for me because they only cost 12 bucks. I've had one mag crap out, but my other seven work like champs.

I also have the CMMG upper, mine is not a tack driver but it's good enough and I don't expect it to be bench rest rifle. Mine came with a POS firing pin that mushroomed out after only a thousand or so rounds. Easy enough to fix but still ridiculous that I had to fix it at all.

The Rock River National Match trigger is not compatible with (at least my) 9mm upper. The height of the hammer is not sufficient to reliably reset and so it either doesn't reset at all, or it goes full auto until it fails to reset. This caused me endless troubleshooting until I dropped in a basic mil-spec trigger - it's all been pure bliss ever since.

I also agree that the ramped bolt is the way to go.

I recall that the H3 buffer is spec for the 9mm upper, but I'm not sure it makes a bunch of difference.

I run 115 or 124 grain plated round nose bullets in mine, the cheapest ones I can find and it loves them. Truncated cone flat points can be troublesome though and sometimes hang on the feed ramp. No issues with hollow points either.

I find the AR with the 9mm upper to be my favorite carbine, hands down. It's a blast to shoot. If you can find a PCC competition in your area, I highly recommend participating. These rifles are only really happy when run fast at many steel plate targets. Despite the initial cost, it's totally worth it.
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