I'm local to PSA, but they are never in stock and thinking about ordering a RRA 9mm carbine instead... are they good to go?  I have no experience with RRA.

GTG.

yes very good

Mine has never done anything but work.

love mine

They are GTG and very under rated. Years ago before the 9mm AR craz they were the only other 9mm AR game in town besides Colt. I've used many of their parts and as far as I can tell they are to the exact specs as my Colt.

I've been researching barrels for my build recently.  RRA is the only 10.5" 9mm barrel I have found that is chrome-lined.  I'm not sure all of their 10.5" 9mm barrels are chrome-lined, but I know they have one that is.  I believe it's made by Wilson, in 4140 CM or CMV.  Colt probably used 4150 CMV, chrome-lined.  RRA's may have a heavier, or thicker, contour than Colt's, and the few reviews I've found on them have all been positive, with respects to accuracy.  They were also the most expensive.

If anyone knows of other manufacturers with 10.5"-11.5" 9mm 4150CMV chrome-lined barrels, please PM me.

They were the first to offer a dedicated 9mm lower. Built my SBR off of RRA components and I've yet to have any form of a malfunction.

Exactly.
RRA made a flattop 9mm years before Colt did.
I purchased one of the RRA 9mm flattop upper receivers and swapped out just the A1 upper receiver on my Colt 6450.
It fit perfectly and even the color matched.

I never cared for their mag block or dedicated lower personally, so I just bought their complete uppers in the past.  Have not had any issues in the 10+ years I've had them.

Some of their stuff is priced a bit on the high side compared to others out there.  Best thing to do is either buy from RRA direct when they have a sale (I believe they have 18% off right now) or buy through a reseller.

I did the same thing.
Purchased a RRA 7.5" pistol upper to use w/Colt 6450 lower. No problems at all.

I bought a RRA 16" 9mm upper from ADCO about 4 years ago and had them ramp the bolt.
It's on a RRA 'multi cal' lower with a Hahn top loading mag block. I've only used Metalform mags and it's never failed to feed or fire.

Not a super accurate setup though, and I'm not the only one who's said that about their RRA. It doesn't like 115 gr. ammo. My Beretta Storm shoots much tighter @ 50 yards.
It does run 147 gr. +P pretty well, and although it's heavy it's UZI tough. Been running nothing but +P thru it for 2 years now.
I wouldn't do that with my Storm or Sub2k.

Colt, Rock River Arms, and CMMG are the original guys for colt mag fed 9mm carbines.
 Jp has also been around for awhile too.

A few others have come and gone over the past 20 years, and a few other companies are still building and customizing.

But....some new companies have recently joined the game, so you do have some choices if you decide to go another route.

It truly is  the "Halcyon Days" of 9mm AR type firearms !!


.

I wouldn't group CMMG in the "original guys" category.  I would say Colt and Oly are OG.  I believe RRA started off offering uppers and conversion kits before they offered full rifles.  There were also numerous others back in the day that offered 9mm stuff (like M1S/Hahn/VMHYtech/ASA/Garrison/Crossfire/etc...), long before CMMG 9mm.  I think CMMG's 9mm offerings have only been around since '07 maybe and I would group them with the newer batch of players that think/thought they could build a better mousetrap than the originals.  I'm not sure how long all the rest of the new players have been around 9mm AR space, but it seems like the last few years have ushered in a bunch of them - some good and some not so good.  Just my memory and opinion from the last 20 years or so.

This is pretty much how I remember this. Colt goes way back of course. I do recall CMMG coming into the game some years back as I got some of their original stuff back when I had more contact with them. I had both RRA and CMMG 9mm carbines and while both were good my best luck was with the CMMG with their dedicated lower. That rifle was great. I know CMMG put a lot of work into their design to improve functioning. My favorite 9mm AR "conversion" was built using a CavArms (now sold under a different name) lower. I had experienced some issues with the early RRA mag blocks in other lowers but when I started using the Cav lower the problems went away. Part of that was my learning curve on how to make a 9mm conversion work.  Today you have so many more factory built options, but you also have this "Glock lower" stuff some just insist on. I am old school, I like the Colt pattern magazines, but its just due to experience with them.

Lots of good information out there now as we have years of empirical data to draw on now.

I bought a complete upper from RRA.   Works perfectly on 3 different lowers.   Very accurate.