Help me choose a 9mm AR15 . . .


March 23, 2008, 10:23 PM
I've been considering an AR for a long time now, but can't justify the ammo prices on .223. I've had a Ruger PC9 for some time now that I like, but would rather have a MORE evil black rifle. I figured it was either an Uzi or the AR, but the choices aren't as clear (for me) on the AR side of things. Given the choice of the following (or others if you wr ant to list some), which would you choose for a factory built (sorry, not assembling one of my own) 9mm AR15?

- Bushmaster Carbon 15
- Rock River Arms LAR-9
- CMMG 9mm M4 bottom of page
- Olympic Arms with a Glock magwell
- Colt 6430/6450
- Other?

Not interested in something that needs to be tweaked to run reliably. I'd just like something that will run out of the box as reliably as possible.


ps. The budget for this rifle is ~$1300, not including magazines.

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March 24, 2008, 12:14 AM
I've had my CMMG for almost 9 months and 3000 rounds -- LOVE IT! It has been utterly reliable and accurate

March 24, 2008, 10:21 PM

March 24, 2008, 10:30 PM
anything that can use Glock magazines seems like a win to me, they are plentiful, inexpensive, feed well, and come in a variety of sizes. Including the extra-evil 33 rounder!

March 24, 2008, 11:03 PM
Why not consider a Beretta Storm? I have one and it has been utterly reliable at a decent price.

March 24, 2008, 11:12 PM
Jackal, I'd keep my PC9 before I'd get a Storm. It's just as reliable and accurate and cost me 2/3 the price. Thanks for the suggestion, though.


March 25, 2008, 07:44 PM
The Olympic model that uses Glock mags appears to have an extra part on the safety side of the lower receiver. I've only see photos but I assume that's some kind of adapter to allow use of the Glock mags. Anyone have any insight on this?

March 27, 2008, 08:54 AM
That's some pretty thin margins. :(

March 29, 2008, 10:42 PM
One last BTT.


March 29, 2008, 10:54 PM
I'll be John Brown if Olympic Arms ain't lost their domain...

Don't click the Olympic Arms links here, popups galore will arrive from the domain squatter.

March 29, 2008, 11:01 PM
The "unofficial" Olympic Arms forum has been down for a few days too:uhoh:.

March 29, 2008, 11:02 PM
I'm sure all have their own preference...I have a Colt AR-15 9mm and its 'great',if you can find one, thats my suggestion.

March 29, 2008, 11:24 PM
if i were to want one i would get the bushy.

March 30, 2008, 10:02 AM
Oh piddle.

I guess I'll have to make a "command decision". I was leaning towards the RRA or CMMG, I guess I'll check out the Colt, too, assuming I can find one. Now I just have to figure out the magazine madness with them (modified Uzi?).

Thanks for the input!


March 30, 2008, 10:39 AM
I have been pondering this same question. Buy a complete rifle? Buy an upper and build out my lower? I was hoping for some good insight in this thread, but not many seem interested. AC

April 1, 2008, 03:00 AM
Check out the Pistol Calibers section on for more advice.

I went with the Standard Olympic 9mm setup. It has a standard .223 lower and does not require any expensive magwells, special buffers, or special hammers. The modified Sten mags are a little bit more expensive, but you can get a mag block for use with unmodified Sten mags.

April 2, 2008, 03:21 AM (

Awhile back I wanted the RRA Model. But they were not for sale at the time. So, I went for the Colt 9mm. I Love this 9mm carbine to death. Cheap to shoot, as well as reliable. To bad the Factory mags are expensive.

Which ever one you choose, I'm pretty sure you would like it.

Zach S
April 2, 2008, 09:41 AM
I would build a colt pattern 9mm because there's more mag options, and plenty of parts suppliers if you break something. Garrison MFG makes a 9mm kit. Just add water, and your lower, and you have a 9mm AR. I've heard good things about garrison as well.

ProMag makes plastic 32 round mags that can be had for $15 or less, CProducts cost around $30, and Colts around $60, when you can find them (and CP is now their supplier, so I dont think Colt will be making any more). You get what you pay for, and the promag is a $15 magazine. I have two, and one runs great, the other, not so much, so they're at 50/50. My Colt mags run great. You can also use modified UZI mags which are about $25 each, but you lose the BHO. You can also get a mag block that allows the use of unmodified UZI mags which you can find for 15 to 20 bucks each. 20 round Colt mags are hard to find and cost a mint when they're for sale. CP also makes 20s for about 30 bucks.

My RRA didnt like the CP mags. Numerous FTEs with them, and only them. I bent the ejector so that it barely rides against the bolt, replaced the rollpin for the extractor with a longer one, shifted the magblock around, added a little more tension to the extractor, blah blah blah. Typical 9mm AR reliabilty mods that I've skated around for the past 5000+ rounds. My #1 mag runs fine now, haven't got to try my #2 mag again yet. Going to the range friday.

From what I've read in the rimfire/pistol cal forum at arfcom, Colts are about the best 9mms you can get, with RRAs in a close second, with BM and OLY fighting for third. Havent read very much about CMMG's 9mm, but if theyre built as well as my 5.56 they're gonna give RRA and colt a run for the money.

Keep in mind that colt builds their 9mms on slickside A1 uppers, and only slickside A1 uppers. No flattops.

I dont like the Oly glock lowers. They just feel wrong to me. I think the bolt catch thingy (actual technical term, lol) on the left side of the magwell ruins it for me.

April 2, 2008, 09:58 AM
The cost difference between plinker quality 9mm vs. 5.56mm is only about $80/1000 rounds. If you want a 9mm AR then go for it, I'm just not sure whether the cost of ammo should be the driving factor.

Zach S
April 2, 2008, 11:53 AM
Where are you buying ammo?

Just for a reference, 1000 rounds of 55gr .223 FMJ from Georgia Arms is $330, $155 more than 9mm 115gr FMJ.

April 2, 2008, 12:11 PM
Being an idiot... I'll ask this question.....
We're nothing 9mm luger rounds are we? I'm sure we aren't but I have to know for SURE SURE SURE!!!

April 3, 2008, 03:19 AM
Where are you buying ammo?

Just for a reference, 1000 rounds of 55gr .223 FMJ from Georgia Arms is $330, $155 more than 9mm 115gr FMJ.

I buy my plinking ammo wherever I can get it the cheapest. :)

For my comparison above I just went to and sorted 9mm and .223 by the 'Total Cost'. I just did it again and came up with a $60 difference. I didn't verify the information but generally I find the info there very accurate.

Zach S
April 3, 2008, 08:28 AM
You said "plinker quality." Wolf does not count.

Once you get past underpowered and filthy ammo that smells worse the inside of my boots after working a ten hour shift at night, then working on my hot rod all day, the difference is still around $140 for cheap stuff.

eta: Sorry bout being a smartass, I didnt intend it to sound like that... Thanks for the link.

April 13, 2008, 12:45 PM
I had a chance to look at an OlyArms non-Glock 9mm AR. Yuck. It was listed as 'new', and if that's new I want nothing to do with them.

I ended up going with the Colt 6450. I may come to regret the expense or flattop-lessness, but I'm hoping reliability will be above the rest.

I'll post pictures when it arrives. Thanks for the input!

Materdei, there are other factors besides cost.

- I don't have anything else in .223, but I do have a couple of pistols in 9mm. Caliber consolidation is simpler for me, and simpler makes me happy.
- In eastern Washington state I had no end of places to go shoot at longer ranges. I'm in the city now and my choices have been reduced drastically. 9mm ARs can usually go to pistol ranges where rifles fear to tread, as I'm sure you know.
- Even if the difference /1000 is only $60, that's money in my pocket that will be needed in the fall when school starts . . .


April 13, 2008, 09:25 PM
Where are you buying ammo? Handloading 9MM with FREE range brass. It doesn't get much cheaper for shooting a lot. I just ordered a 9mm RRA A4 with the 9MM integral mag well lower. Waiting patiently, well pretty patiently. ;)

April 24, 2008, 10:29 PM
It finally arrived. The Colt 6450. I'm pleased as punch so far.

Thanks again for all the replies. ( (

Doc S
April 25, 2008, 01:58 AM
I've had a few different pistol caliber ARs. 3 were in 9mm and one in 40 S&W.
One was a RRA. It was ok, but I didn't like changing the hammer and other parts out (buffer etc). I tried an Oly 9mm upper with a mag block and standard Sten mags. It was fun and reliable. I could use any of my lowers without changing anything but the upper!
I decided it would be kind of nice to have one that used Glock mags, since I had a G17, so I got the OLY with a Glock magwell. It's been great! Never had a problem with it at all and it's accurate. I decided I should get an upper in .40S&W to go with it, since all I had to do was change uppers and use G22 mags. It also worked fine, but I decided it would be nice to have a designated lower, so I got a standard Stag lower and bought some mags from Oly with a block welded on the mag. It works well on both types of lowers...

Here's my Oly 9mm in Glock configuration.

Here's my Oly .40S&W upper with Stag lower.

God Bless,
Doc S

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