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View Full Version : Up-close comparison of RRA 9mm vs Stag 223


grammaton76
09-23-2008, 2:31 PM
Ghettoshecky was kind enough to loan me a RRA 9mm upper recently, so I could satisfy my curiousity about how exactly these 9mm uppers work. I took a metric crapload of comparison pictures between the RRA 9mm and my Stag Arms 223 upper. Here's the link:

http://thegunwiki.com/Gunwiki/AnalysisAR9mmRRA

I'd appreciate any insights folks may have about anything that's wrong in the article. There were a number of notches, holes, etc that I couldn't quite identify a purpose for. If you guys can figure it out, please share!

http://thegunwiki.com/pub/Gunwiki/AnalysisAR9mmRRA/s_UpperComparison04574.jpghttp://thegunwiki.com/pub/Gunwiki/AnalysisAR9mmRRA/s_Bolts04624.jpg

Bowser
09-23-2008, 2:40 PM
Cool. I know the 9mm build has no gas system, so I'm wondering can I just move the front site to accommodate a midlength rail system easily?

apbrian112
09-23-2008, 3:06 PM
good write up with nice pics. however, aren't there only 2 variants out there?
the colt and the olympic. the article makes it sound like there are 3, the colt, olympic, and RRA. the RRA is a colt-type system which is why the parts between the 2 manufacturers are interchangable.

apbrian112
09-23-2008, 3:07 PM
Cool. I know the 9mm build has no gas system, so I'm wondering can I just move the front site to accommodate a midlength rail system easily?

listen to randall...

savasyn
09-23-2008, 3:15 PM
Dang, that was a lot of work you did there. Nicely done!

I recently got an RRA 9mm upper and have been having a lot of fun with it.

I use the Hy-Tech (http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=135516&t=11082005) mag block with mine and there is no alteration needed for the UZI mags.

grammaton76
09-23-2008, 3:27 PM
Dang, that was a lot of work you did there. Nicely done!

Thanks

I recently got an RRA 9mm upper and have been having a lot of fun with it.

I use the Hy-Tech (http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=135516&t=11082005) mag block with mine and there is no alteration needed for the UZI mags.

Yep - unfortunately however, I've read that the Hy Tech is no longer in production.

grammaton76
09-23-2008, 3:28 PM
good write up with nice pics. however, aren't there only 2 variants out there?
the colt and the olympic. the article makes it sound like there are 3, the colt, olympic, and RRA. the RRA is a colt-type system which is why the parts between the 2 manufacturers are interchangable.

Are you sure the Colt is 100% identical to RRA? I'd heard that RRA was related and that some parts would interchange, but not 100%. I'd love it if you could unearth info to the contrary.

hybridatsun350
09-23-2008, 3:39 PM
Great write-up!

I will comment and say that the 5.56 upper looks a bit dirty. ;)

grammaton76
09-23-2008, 3:45 PM
Great write-up!

I will comment and say that the 5.56 upper looks a bit dirty. ;)

I wondered who would point that out first. :) It was indeed dirty, but it looks even worse by the fact that the RRA's never been shot to my knowledge. :)

grammaton76
09-23-2008, 4:22 PM
Interestingly enough, I just remembered Model1Sales puts out 9mm uppers as well. Not sure which system they're with, although looking at their 9mm adapter (below), it bears some resemblance to the RRA one.

However, the hook / bolt hold open widget is different, and the frame of the adapter is very different from the Hahn magblock I analyzed (although probably not in a way that matters to the mag or the rifle).

http://www.model1sales.com/item-detail.cfm?ID=LRPMWC9&storeid=1&image=9mmagwell.gif&CFID=41558125&CFTOKEN=91384388

ar15barrels
09-23-2008, 4:40 PM
Cool. I know the 9mm build has no gas system, so I'm wondering can I just move the front site to accommodate a midlength rail system easily?

No.

The barrel diameter is smaller forward of the current front sight base.
You could put a mid-length or rifle length rail system and mount a sight on the rail though.

ar15barrels
09-23-2008, 4:41 PM
yes, just like a dedicated 22lr AR, the front site (if there is one) is just so the standard handguards have something to clamp into, and also obviously to have a site up front.

:nono:

ar15barrels
09-23-2008, 4:42 PM
Are you sure the Colt is 100% identical to RRA? I'd heard that RRA was related and that some parts would interchange, but not 100%. I'd love it if you could unearth info to the contrary.

Barrels, bolts, recievers, mags and magazine adapter blocks all interchange.
Not sure if the firing pins match or not.

ar15barrels
09-23-2008, 4:44 PM
Interestingly enough, I just remembered Model1Sales puts out 9mm uppers as well. Not sure which system they're with, although looking at their 9mm adapter (below), it bears some resemblance to the RRA one.

Almost everyone follows the colt pattern in 9mm uppers.
Only Olympic is the orphan child.
Bushmaster may also be different.

apbrian112
09-23-2008, 4:57 PM
:nono:

blah... i misread his question... i thought he wanted to completely remove the front site base and run a mid-length free float, ala running a rifle/mid length FF on a carbine gas system utilizing a low-pro gas block...

apbrian112
09-23-2008, 5:02 PM
Cool. I know the 9mm build has no gas system, so I'm wondering can I just move the front site to accommodate a midlength rail system easily?

if you wanted to just drop in some rails (non-FF), RRA has their 9mm midlength upper available. just take off the handguards and drop the rails in.

grammaton76
09-23-2008, 5:07 PM
Barrels, bolts, recievers, mags and magazine adapter blocks all interchange.
Not sure if the firing pins match or not.

Very good info. I particularly appreciate that if you don't know something for sure, you don't claim to know it.

I recently had a turkey send in a comment to my SU-16 article a while back, telling me that the SU-16 uses an AR-15 firing pin (wrong!).

Anyway, I've added your bit over here:

http://thegunwiki.com/Gunwiki/RefARcal9mm

If you know of any other manufacturers of 9mm uppers, I'll be happy to list 'em.

apbrian112
09-23-2008, 5:08 PM
cmmg makes some
garrison mfg
asa

Jpach
09-23-2008, 5:13 PM
I looked on model1s website, I didnt see any 9mm uppers, are they special orders or something?

grammaton76
09-23-2008, 5:13 PM
cmmg makes some
garrison mfg
asa

Ah yes, forgot about them - thanks. However, I've put them under "unsure" because their website, as of this moment, doesn't have any 9mm products available that I can find. They mention 'em in the titles of the pages, but when you look for actual products, they don't have 'em.

REDHORSE
09-23-2008, 6:22 PM
Good job.

Just one minor correction IMHO. The plastic spring loaded block next to the ejection port isn't a "brass deflector".

It's a "gas deflector". Since, the 9mm is blowback... you get a lot of gas coming back at the shooter through the ejection port. The plastic block redirects the gases away from the shooters face.

redcliff
09-23-2008, 6:23 PM
Thanks



Yep - unfortunately however, I've read that the Hy Tech is no longer in production.

Hmm Brownell's lists them as in stock. Where did you see they were out of production?

As the owner of a registerred Uzi and Registerred Colt AR-15 I've found the VM Hytech adapter a wonderful addition to my RRA 9mm upper.

grammaton76
09-23-2008, 6:33 PM
Hmm Brownell's lists them as in stock. Where did you see they were out of production?

As the owner of a registerred Uzi and Registerred Colt AR-15 I've found the VM Hytech adapter a wonderful addition to my RRA 9mm upper.

Ah, actually I shouldn't have said read - Ghettoshecky's brother (the actual owner of the upper) had been trying to find 'em and he'd read that the Hytech's were out of production.

Looks like they're still around after all! That's good news for folks with Uzi mags.

I just wish there were a Sten mag kit for me that didn't involve buying Olympic sooner or later.

grammaton76
09-23-2008, 6:43 PM
Good job.

Just one minor correction IMHO. The plastic spring loaded block next to the ejection port isn't a "brass deflector".

It's a "gas deflector". Since, the 9mm is blowback... you get a lot of gas coming back at the shooter through the ejection port. The plastic block redirects the gases away from the shooters face.

Added into the writeup. It's contoured right for that, I suppose. Still sits a little funny with me, but it's definitely closer than anything I had come up with.

REDHORSE
09-23-2008, 6:49 PM
Hmm Brownell's lists them as in stock. Where did you see they were out of production?

As the owner of a registerred Uzi and Registerred Colt AR-15 I've found the VM Hytech adapter a wonderful addition to my RRA 9mm upper.

Ditto.

Having a Reg UZI and ARs, VM-Hytech only made sense... since I have plenty of hi-capacity UZI mags.

slick_711
09-23-2008, 11:23 PM
Awesome write-up and comparison. I have yet to actually handle one of the RRA 9mm uppers. I've shot a Colt or two but had never field stripped them. So I thank you for enlightening me. Now I want one.

Funny, I also want a Kaiserworks lower. Future project brewing...

I'd like to contribute a small answer to your project. Toward the bottom you have some pictures and commentary which point out the small scallop in the upper receiver. From the bolt design on the 9mm I'd say it doesn't need to be present for the 9mm upper (but the uppers look like they're identical when completely stripped?). In the .223 that scallop's purpose is to allow the bolt to rotate and lock up. This is one of those "doh I knew that" moments for you I'm sure Grammaton. :)

BamBam-31
09-24-2008, 2:21 AM
Wow, nicely done! Getting my RRA 9mm upper on Friday, so I can do a side-by-side as well!

DHiggmo
09-24-2008, 3:20 AM
Vary nicely done! The only thing I could think of improvement would be showing photos of Uzi mags inserted in mag block. Do they make different Mag blocks so you can use sten mags?

ar15barrels
09-24-2008, 9:21 AM
Vary nicely done! The only thing I could think of improvement would be showing photos of Uzi mags inserted in mag block. Do they make different Mag blocks so you can use sten mags?

http://ar15barrels.com/tech/hytech-block-mods.jpg

There is a block set (2 piece) for sten mags as well.

DHiggmo
09-24-2008, 10:54 PM
http://ar15barrels.com/tech/hytech-block-mods.jpg

There is a block set (2 piece) for sten mags as well.

Sweet!! Thanks

REDHORSE
09-26-2008, 5:53 PM
RRA Mag block. I labeled the pic, but I don't recall if I took the picture or found it online.
http://img48.imageshack.us/img48/8121/9mmmagadapter6xa.jpg

Picture of my VM Hy-tech, before painting FDE.
http://img527.imageshack.us/img527/6168/hytechbzs5.jpg
My VM Hy-Tech didn't require AR15barrel's modification.

You can use it on your webpage if you want.

ar15barrels
09-26-2008, 6:53 PM
The bolt hold open on the top block also works with the C Products mags which have the rib down the back of the mag tube and the follower to activate the bolt hold-open.

REDHORSE
09-26-2008, 8:02 PM
The bolt hold open on the top block also works with the C Products mags which have the rib down the back of the mag tube and the follower to activate the bolt hold-open.


yep, that's just an old picture... before C-Products came out with their Colt style mags.

Riodog
09-26-2008, 8:36 PM
Nice write-up Grammaton76, I use all RRa lower parts and mag block with my Colt upper. Works flawlessly.

If some one needs them, I have a set of original Colt magazine blocks I haven't any use for. BE ADVISED, they are a real job to install correctly and I would not advise a do-it-yourselfer try unless you are extremely competent. You'll wind up messing up an oll if you goof.
Pm me and I'll drop them in the mail. I'd really rather they went to Randall or someone with gunsmithing skills.
Rio