By: Cary Kieffer
Did you ever want an AR in 9mm? I did and for a lot of reasons they make sense. Generally, I am a Rock River and SIG 516 fan and they make up the bulk of my rifles. I did want to build a budget beater PSA 9mm AR and preserve my two 1000$ plus dollar Rock River 9’s. I started with a PSA 9mm AR pistol kit and a stripped receiver. Let’s see how all that turned out.
Why would I want a 9mm AR? For starters I’m paying under 20 cents a round for factory loaded 9mm, while 5.56 is at least 35ish cents roughly for anything decent for those of us not reloading. Furthermore, I can really quiet the thing down with a Can, 147 and 158 grain 9mm is subsonic and obviously will cycle the action where I don’t have a single 5.56 that will cycle subs. Of course there is the 300 Blackout but again near a buck a round for subsonic ammo. The 9mm will pay for itself in quiet subsonic ammo pretty fast. I like the Blackout and own a couple but for informal shooting which is the vast majority of my range time, cheap is better and 9mm is cheap.
The PSA 9mm AR Pistol Kit: I got the kit for 550$ from PSA, it showed up fairly quickly but with one small glitch. They put in a collapsible carbine stock and carbine buffer tube. See the problem there? So they sent me an instant felony kit. Fortunately, I knew better than to assemble it and simply ordered a PSA pistol tube kit from Ebay, no biggee and I didn’t bother to call PSA. I knew I would eventually use the rifle stock kit. The kit looked pretty good out of the box and came with a 10.5 inch barrel.
Assembly: The lower was a snap, I used a stripped Anderson Manufacturing receiver so it can be registered as a pistol. The magwell block slides right in from the top and is held in by the bolt catch. I would have liked to see it sit more snuggly but I haven’t had any issues with it. In fact I had zero malfunctions of any kind with that magwell block, I don’t see a reason to drop 175$ on a RRA block. This one worked fine.
The 9mm specific trigger pull isn’t terrible, by no means what I love but it’s ok, once I get the bolt ramped I will switch to a better 5.56 trigger group. It was an uneventful build and all the stuff seemed pretty good. I took my “safety inspection” sheet in to the county Sheriff for registration (cause that’s what it is in Michigan, registration) How can you have a “safety inspection” if you’re not supposed to bring the weapon?? So once registered I had my new PSA 9mm AR pistol ready to shoot.
Shooting: I shot the hell out of it the first time out. Accuracy was excellent, shooting 2 inch groups with most loads at 50 yards. The Metalform magazines worked like a champ and actuated the bolt catch perfectly every time. I was super happy and then somewhere around shot number 375 the bolt key sheared off. Bummer, not only was the gun down for the day but it was really seized up good as you can see from the pics. I ended up having to take off the pistol tube and stuff to clear it out the back and get the thing apart. I hadn’t noticed it at first but the key is only held on by one bolt. That kinda rubbed me the wrong way, I’ve never seen one NOT held on by two grade 8 bolts. I took it to Jim Garrison at Johnsons Sporting Goods in Adrian MI. Jim is the new full time school trained gunsmith there and he is greatness waiting to happen I think. The kid has his head and ass wired together and I trust him implicitly, so if you’re in the area, I highly recommend him. He said a classic case of over tightening from the factory. The single bolt had started to crack from over tension and gave up on me. We talked about a weld and a new bolt but just went with a new bolt. I will eventually replace the key with a RRA factory key and then have the 2 bolts I should have had to begin with. All in all no big deal really and a fixable issue. The last issue I had with the kit was the barrel was NOT beveled around the chamber. So I had to yank the barrel and give it a bevel all the way around which GREATLY added to smooth feeding. This is something your going to want to do, trust me it’s worth the dremel time.
Reliability: Since then I have put a good 2 cases through it. I had a few FTE’s early on, no rhyme or reason or any pattern I could see. I felt the block was fine and ejector wasn’t the issue. After comparing the PSA bolt carrier with a RRA bolt I decided the extractor tension was the cause for the occasional FTE. The PSA wouldn’t hold a round of ammo on the bolt face at all out of the gun, where the RRA would. Again no big deal, I popped out the extractor and worked it over with the dremel a tad and with more tension I felt it was fixed and it ran 100% for a short time. Soon though it started doing it again. (FTE’s) One more time I pulled out the extractor and started to give it a slight bend and SNAP! Right in half. The thing looked like it was made of melted down Matchbox cars, very porous and crappy looking metal. I replaced it with a factory RRA extractor and haven’t had a problem since.
Subs and a Can: The real joy of shooting this is suppressed with PPU 158 grain ball. The thing is ridiculously quiet. It’s Kelly’s favorite toy, she loves the thing. I do too and it would make an excellent HD gun with a faster load, 32 rds of 9mm coming out of 7.5 inches is probably faster than usual. A good +P hollowpoint (which it feeds fine) would definitely ruin some bad guys day and not even be close to ear shattering even in your house.
Summary: The kit is ok if you are prepared to tweek it some. It’s cheap, fun, accurate and reliable with some work on the BCG and barrel. Definitely check out your BCG for a bad key bolt and check your extractor tension. (or just replace it with RRA) That’s it, easy fixes if you think they need it. Make sure you don’t assemble a rifle lower and a pistol upper like they sent me, at least not without a Stamp back from the ATF. All in all for the 600$ with the stripped receiver cost added in you will have a ball with this thing, lot’s of fun and a serious money saver feeding her 9mm.
I have since done several 9mm builds and shot the hell out of them too. Review coming one of these days. Those builds I decided to skip the PSA kit based solely on the quality of the PSA BCG. I went with a CMMG BCG and a RRA dedicated 9mm receiver. The CMMG BCG comes ramped so I could use a 2 stage match trigger which was great, no dedicated 9mm hammer in this one. A much pricier build but I feel it was worth it. If you want to get out cheap though, check out this PSA kit.
As always thanks for reading and train often.
Cary Kieffer
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Solid, informative post. I’m thinking of building an AR9 pistol for my wife, for when I’m dead (pancreatic cancer) so she won’t have that lonely feeling in the night. Have one in 556, 10.5 barrel, Shockwave, but it’s kinda fierce. May just build a new upper; time and energy are limited.
First off I’m sorry man, that’s the worst, I know, my brother in law just passed from it a few months back and he was a year younger than me, he never made 47. So I’m sorry…
Anyway, my 9mm building has evolved alot since that was written years ago. I’ve done 20 or more since. I have a tried and true system of good stuff that will last a lifetime. I generally buy stuff in bulk. If you want to get with me, I’ll get everything together you need and assemble it for you. All you’ll have to do is install the mag block and I could teach my dog to do that. It’s perfectly legal to ship an upper, so I will do it for cost to the penny for ya. Just let me know. Thanks. Cary
Ca**@ta***************.com
Cary, thank you! I’ll be contacting you offline, with AR9 in the subject header.