9mm AR compatibility

[Ashton1911]

The world of AR15 is defined by mil spec. Nominally, any part will fit on any other manufacturers part. PSA, Aero, CMMG, and many others all make some variety of 9mm ar pattern. How many of them have interchangeable uppers?
PSA says you must use their upper on their lower, but life might be a lot nicer if you can match other uppers with the cheap PSA 9mm glock compatible lower.

 

[Mgderf]

The world of AR15 is defined by mil spec. Nominally, any part will fit on any other manufacturers part. PSA, Aero, CMMG, and many others all make some variety of 9mm ar pattern. How many of them have interchangeable uppers?
PSA says you must use their upper on their lower, but life might be a lot nicer if you can match other uppers with the cheap PSA 9mm glock compatible lower.

Not much compatibility between manufacturers.
Much like the AR10 platform, they sort of threw the standardization idea out the window when they started developing the AR9's.

I have a PSA 9mm upper on a PSA dedicated 9mm lower and it works great.

 

[Ashton1911]

Aero says they would work on any 9mm lower, but PSA says on their own platform. Others are not clear, and I don't have the money to play around with them to see what plays well with which system.

 

[Simon6101]

I have 4 AR9's. Only 1 is a factory built. I have a Stern Defense upper on a Sharps Bros lower, some no name on a CMMG , A parted upper on an Anderson lower,. I know I have a Spikes lower with i Think an Anderson Upper on it. What is the issue?

 

[Cameramonkey]

Its not true of all uppers. Especially PSA. Mine sits on one of several lowers depending on what I want to do with it.

Unless they have changed something, they are probably trying to CYA in case some rando lower isnt to spec.

EDIT: I just checked, and my current 9mm carbine setup is 95% PSA. PSA upper, "Multi Cal" PSA lower, and a colt pattern magwell insert. (not PSA) Works fine.

So unless they are ALSO doing something funny with their lowers, they are full of it.

EDIT2: I wonder if they are concerned about other MFRs that ARE proprietary and not compatible with anyone else's and are afraid of their customers mating those oddball lowers to their uppers?

 

[nipprdog]

I have a PSA 9mm upper on a PSA dedicated 9mm lower and it works great.

Same here. I've had a colt mag version, then a 16" glock, and now an 8" glock model. All have been flawless.

 

[Ashton1911]

would be interested if someone has a cmmg radially delayed blowback upper on a glock compatibly lower, and which lower you chose to go with. Could I just grab a PSA and expect it to work?

 

[Cameramonkey]

would be interested if someone has a cmmg radially delayed blowback upper on a glock compatibly lower, and which lower you chose to go with. Could I just grab a PSA and expect it to work?

Send me the funds for that upper and I'll happily buy and test it for you. I'm just that nice of a guy.

I THINK you are fine doing so. I am 99% sure all the proprietary parts are contained in the upper/BCG.

I want one because I hear that the are nice, but I just cant justify the cost, personally.

 

[Ashton1911]

The upper is nice, and I think is the cheapest delayed blowback ar pattern upper. The lower adds no value, especially for the price. 7-900 for an upper is a whole lot better than 1500-1700 for the full gun.

 

[Mongo59]

Kind of like when the Mex comes out of the desert in the "Good, the Bad and the Ugly" and takes all the single actions apart and tries to make some super weapon. Not much chance of that here in the real world...

 

[Mgderf]

The upper is nice, and I think is the cheapest delayed blowback ar pattern upper. The lower adds no value, especially for the price. 7-900 for an upper is a whole lot better than 1500-1700 for the full gun.

This may be true now, but I bought my PSA AR9 as a stripped PSA AR9 dedicated lower that I built up, then added the complete upper.

I didn't want the hassles I've read about with the mag well adapters.

I took my time and bought everything on sale.
I can't recall exactly how much I have in it, but I remember it seemed reasonable at the time.

 

[Altrex]

would be interested if someone has a cmmg radially delayed blowback upper on a glock compatibly lower, and which lower you chose to go with. Could I just grab a PSA and expect it to work?

The problem with the glock lowers is that the ejector has to be removed and the mag height has to be retained at the correct height. I use the cmmg rdb with a standard ar lower and endo mags. I really like that setup.

 

[Cameramonkey]

The upper is nice, and I think is the cheapest delayed blowback ar pattern upper. The lower adds no value, especially for the price. 7-900 for an upper is a whole lot better than 1500-1700 for the full gun.

THey are definitely smooth. But a straight blowback 9mm isnt bad. So I dont think there is enough improvement for the cost. Just my .02

I didn't want the hassles I've read about with the mag well adapters.

Ive had great luck wth the colt stick adapters. So if you have a lower with premium upgrades you really like, go for an adapter.

 

[Ashton1911]

They are definitely smooth. But a straight blowback 9mm isnt bad. So I dont think there is enough improvement for the cost.

If suppressed, I believe that locking breeches are more important, rather than to reduce recoil, reduce gas in the face. If anyone has experience running the CMMG upper suppressed vs blowback uppers suppressed, please enlighten me.

 

[marvin02]

Site with a lot of info on AR9s:

Blowback9.com

No-BS information for the 9mm AR.

blowback9.wordpress.com

 

[Cynical]

I literally finished mine a month ago and bought a billet upper from Delta Team Tactical and put it on an Aero precisión lower. Barrel came from there as well. I wound up using Endomags cause I have gobs of pmags and don’t own a glock. With the price of a magwell adapter it was enormously cheaper to go with Endomags. Everything else I used was all mil-spec. I wished I had done a little more research before I built it because I bought a solid buffer and put 2 bucks worth of quarters in the tube because it was too short. Have since bought a sliding weight buffer from KAK industries to eliminate the chance for firing a round out of battery because of bolt bounce. It is so fun to shoot I wish I had built one years ago. Good luck and have fun.

 

[92FSTech]

THey are definitely smooth. But a straight blowback 9mm isnt bad. So I dont think there is enough improvement for the cost. Just my .02

I've had both, and after building my CMMG I'd never go back to straight blowback. I built mine before the parts got so stupid expensive, and it lives very happily on an Anderson lower with a Larue MBT-2S in it, and is fed by the endomag pmag conversions. I think I have under $800 in the whole setup. It was definitely worth it for that money...for what they're asking these days, I dunno. YMMV.

My straight blowback gun was a PSA on a Glock mag lower. I hated that thing so much that when I traded it off towards a Marlin 1894 I was almost more excited to be rid of it than I was about my new 1894. In contrast, my CMMG is one of the last guns I'd ever sell.