I have a factory built complete RRA 16" A4 CAR upper and I built a RRA stripped lower with RRA LPK, Hahn top loading mag block, Colt and Beta C mag and ACE M4 SOCOM buttstock.
My build was smooth, no problems and it runs fine.
Here is my Colt I love it!
DT!
I’ve got a Colt SMG upper on a RAA 9mm pistol lower. It takes Uzi mags. The only drawback that it has is no last round hold open. The pistol runs great, and there isn’t hardly any recoil.
“Eric,
I have the same uzi mag block. I just got it and installed it in a PWA lower where it fit fine. But when I mate it to a RRA 9mm upper something in the block doesn’t allow a flush fit. Do these blocks require minor smithing?”
I am building a 9mm RRA as well. I got the 9mm RRA midlength and an RRA 5.56 lower. I then installed the ASA magblock. My 9mm buffer and hammer haven’t arrived yet :mad: but I decided to put togeather what I could just to see what my baby would look like completed. Problem is that the upper and lower wouldn’t fit! I thought it may be the magblock and removed it then tried to close the upper and lower. No go. I can match the front pin and receiver ends but there’s a tiny bit at the rear end that wont go in (I have to push it a little and even then the rear pin won’t go in! I ended up leaving it with a gunsmith to check the fir of both receivers. I read somewhere that some RRA 9mm upper receivers require a tiny bit of “Tweaking” (from the other AR forum:
“Also, about 25-30% of the time the Rock River Arms setup requires a little “Tweaking” to get it running properly. the most common problem is that it will not strip the last 1-4 rounds out of the Uzi mag, the reason being that the Uzi follower has too steep and angle for the bolt to strip the rounds. This is easy to fix with about two minutes a mag and a pair of pliers (just did it myself) and the mags will still work in an Uzi, but some people don’t like having to “tweak” their weapon to get it to run. Also, you might have to get another hammer- the DMPS style AR15 hammer (looks basically like an M16 hammer with the back “rat tail” choped off) works for both .223 and 9mm. Many AR-15’s are equipped with a hammer that has a small face out of the top front, and that can hang up on the bolt carrier and cause a bad jam. Figure $15 for a new hammer from Brownells. One final thing that many people do is have the bolt “ramped” as the 9mm bolt can beat kinda hard on the hammer and pins. It is not necessary on a semi lower, the full autos are the ones that seem to get beat pretty hard as they fire so many rounds, but I perosnally figure “it can’t hurt.” LRM firearms does this service for $35” )
So it is possible that a bit of Gunsmithing may be required to get your AR (and mabe mine) to run properly. Mind you this seems to be the exception rather than the norm. Has anybody else had problems with their 9mm AR builds?
I have an Olympic that takes the Glock mags. I love it. It has been really good to me…100% reliability, good trigger, and shoots pretty accurately. Of course, the brand name is cursed…
I started out with a Colt LEO 9mm AR back in 2001. It was the most unreliable POS I’ve ever owned. I tried converted Uzi mags and factory LEO 32-round Colt mags, too. It wouldn’t feed any shape cast bullet reload, no JHP’s, and not even FMJ unless the bolt was absolutely dripping wet with oil.
I swore off pistol caliber AR’s after that deal until I shot my friend’s Olympic .45acp AR. It fed any shape cast bullet we tried, even down to 165gr SWC’s and light loads. After that, I looked for one immediately, bought it, and it’s been completely trouble free after thousands of rounds. I’m going to complete one of Justin’s AR45 lowers for it so I can use M3 Grease Gun mags to get away from the expensive .45acp Uzi mags.
When I decided I wanted another 9mm AR, I wouldn’t buy anything but Olympic after the experiences I’ve had. I found one that supposidly only had 400 rounds through it with two Oly converted STEN mags for $400 shipped. It did come in looking like new and has proven to be 100% reliable. I’ve shot a full .50 cal ammo can full of my 147gr cast bullets from wheelweight alloy and homemade lube. In all of those rounds, it’s only seen one cleaning. I just spray the bolt with Remoil before I shoot and it just keeps on going. With my alloy/lube/sizing combo, I get no leading, either. I like it so much that I just bought another 30 WWII British STEN mags from Ohio Ordinance that I’m going to weld the square tubing to and mill the slot on, just like Olympic does.
At the same time as I got my Oly, my neighbor traded into another Colt 9mm AR. The same thing happened with his as my old one. It’s extremely ammo picky and will not feed well with both the Colt and converted Uzi mags. He does have one Bushy polymer mag that feeds well with FMJ and my cast bullet reloads, though.
For a trouble-free pistol caliber AR, Olympic is the only wya to go, IMO. I’ve owned or fired three Colt 9mm AR’s, and they have all been very ammo picky. My Oly feeds anything I stuff in the mags.
Here’s my setup. It’s an Oly 9mm upper, Eagle Arms/Armalite lower, DPMS lower parts kit (you don’t need a special hammer for the Oly pistol caliber AR’s!), Yankee Hill Machine rail forend, Knights Armament vertical grip, Streamlight Strion rechargable 70 lumen flashlight and a Trijicon Reflex with the dot recticle. Mounted on the YHM forend, it cowitnesses perfectly with the factory sights and with the large rear aperature, it’s the same size as the outside of the Reflex, so you don’t even notice the rear sight.
I just bought an aluminum collapsable buttstock for it and I’ll put on my Blackhawk single point sling mount to use with my ZM Weapons system bungee sling. I’m also threading the barrel to install a 9mm A2 flash hider. I have several Colt pre-ban lowers and I’ll use one of them for it (since I live in MA 
). At the next gunshow, I’m getting a light gray (Colt colored) A1 slab sided upper receiver and drilling it for the Oly ejector and the colors will match with the lower I’m going to use with it. MA laws suck.
Here’s the pic of the work in progress.
Does this mean I cannot just drop in the RRA 9mm upper onto my RRA lower?
I just bought a Colt 6450 and a Magpul CTR and MIAD for it. I’m also planning to order a YHM Wraith QD for it as well.
Hope to get to shoot it for the first time tomorrow.
Rob, did you SBR it already? If so, did you go with the SD type upper or an A2/A3 shorty upper?
I’m still debating which route to go with my 6450.
I haven’t SBRd yet. I’m waiting for Grant to offer his 9mm SBR uppers. I’ll probably start the paperwork shortly though. Still trying to decide where I want to engrave it.
Above the trigger…brother. High CDI factor there. 
Shot the 6450 today to zero it at 50 yards. Two clicks to the right and it was zeroed right out of the box. Blew the center diamond out of a shoot-n-see gridded zero target without problem.
The one thing I wasn’t expecting is that it kicks more than my 5.56 ARs; by quite a bit. Granted, with the table/rest I had available to use it wasn’t exactly in the pocket, but I guarantee you I’ll have a bruise tomorrow after just 40 rounds of Blazer aluminum.
More felt recoil is from two reasons.
- You pushing at least a 115gr round (or more) down range (heavier than 55gr .223)…physics.
- More reciprocating mass…the carrier and buffer are heavier than a M16 carrier…physics. (this is the reason why I’m shooting a 1/2 circle unshrouded carreir an a CAR 2.9oz buffer in my 3gun rifle. I may soon try a JP low mass carrier soon too).
40 rounds give or take. 20 before the two clicks, 20 after. I think you can see the results of some of my flinches.
I have a stock Colt’s and like it. My sons and I sometimes shoot plates with an ML3 mounted on a PRI gooseneck mount. That makes it hard to miss!
John
I’d like to hear more about these SBR uppers.
You are joking about the recoil and bruise, right? Yes, there is a little more felt recoil, but not THAT much!
No, not kidding. The benches they make you use at that particular range meant that the stock was sitting right on the ball of my shoulder and not the pocket. I didn’t wind up with a bruise but it was definitely sore the next day.
Anything more than a .22 will leave you sore if you don’t hold the gun correctly.
Sore from a 9mm AR? :eek: