View Full Version : RRA 9mm and PRI Gas Buster Charging Handle Problem.
I just picked up my 9mm SBR from my gunsmith. Its a factory Rock River Arms 9mm upper with Stag Arms lower and LPK, RRA 9mm hammer, Hahn dedicated magazine block
Here's my problem the upper work fine with standard changing handle when insert the PRI gas buster - it slides in and out fine without the 9mm carrier.
If I insert the carrier its very hard to pull the (charging handle / carrier) out of the upper finally when I assemble the upper on a lower the I can't charge the firearm. Everything just binds.
Once again everything works fine with standard charging handle. Bolt locks open on empty mag, charges fine.:confused:
Anybody encountered a similar problem?
Thanks in advance.
Robb Jensen
02-19-08, 07:48
The carrier key on a 9mm bolt is different than on a 5.56mm bolt carrier. The 9mm probably just doesn't fit the PRI Gas Buster correctly. I'll measure a 9mm key at work, it's either taller or wider.
Can you put a caliper on the carrier key of the 9mm and compare it to a 5.56?
It sounds like the key is too large on the 9mm and it's causing the GB to "swell" and fill the channel.
I'd be interested to know:
OD of the 9mm carrier key where it fits into the GB
OD of a 5.56 carrier key that works with the GB where it fits into the GB
ID of the GB slot
ID of the slot of the CH that works with the gun
Thanks for the replies.
Rob
I'm at work but I'll measure everything this evening and post it.
Paul
I have a PRi on my 9mm upper and it works nicely.
Colt 9mm SMG bolt group, RRA 9mm upper, and Hahn dedicated block.
I bet the lower has the Hahn block setting up to high and is pushing the carrier key into the charging handle.
The only difference in my set up is that I'm using the RRA carrier group.
ETA I don't think the the height of the Hahn block because if I have the upper separated from the lower when the PRI goes into the upper all by itself its moves freely - when the PRI and carrier group go together it starts to bind (I can still move it but it has noticeable resistance.
Now If I assemble the upper and lower together it binds completely.
Could you measure the width and height of your Colt carrier key?
Thanks
Paul
On my 9mm, most of the blowback comes out of the ejection port, and the gasbuster I tried didn't seem to do anything. I put it on a 5.56 gun, and used the regular CH on my 9mm.
I bet the lower has the Hahn block setting up to high and is pushing the carrier key into the charging handle.
I'm not sure that is his problem because he indicates that he has a Hahn dedicated magazine block (according to his original post). The dedicated blocks are dropped in from the top and are not adjustable unlike those adjustable blocks put in from the bottom and set and placed with an allen screw. Good suggestion though !
...and yet my Hahn dedicated has creeped up under F/A fire just enough to create drag on my carrier. :eek:
Robb Jensen
02-22-08, 04:20
I thought we had a 9mm RRA in stock so I could measure it's key, we sold it last Saturday. All these non Colt 9mm problems make me want to buy a Colt upper and use a Colt block and pin it in my lower when I get around to converting one of my SBRs into a 9mm.
Guys
The bind happens with the upper separated from the lower. I'm pretty sure its the RRA gas key width. Since it has no effect on 9mm function I could get it machined to fit the Gas Buster, the question is, is it worth the effort?
To be honest, if the RRA carrier created issues with any charging handle, or upper I owned, I would dump it and get a Colt unit.
I'm not a Colt guy, but in this area, they excel with uniformity for most parts. RRA most likely only cares to make sure their parts work with their parts.
FWIW...
Where can I find Colt 9mm carrier? Thanks
You could start with SAWLESALES.com. They will probably be the highest priced unit, but they have them in stock most times and they're new.
Other than that, I looked around the various internet sale boards to find mine.
You might have to buy a Colt 9mm upper, steal the bolt, and then sell the upper. :(
SAW wants $329 for 9mm carrier :mad:
As I said, they are not cheap. They are, however, the best.
If you go that route, get the more expensive one @ $395. It has been ramped and tungsten weighted, which he normally charges $199 to do by itself.
Yikes, $325 for a carrier alone? Maybe I should part out my Colt 9mm....
How much do they want for a complete 9mm BCG?
Rob
There is no bolt in 9mm. Technically bolt is part of carrier.
SAW sells the standard 9mm carrier for $329 and improved/ramped/tungsten wighted for $395.
ETA - Maybe I can just purchase Colt 9mm gas key from SAW and mate it to RRA bolt. The gas key is $51 so much cheaper.
Paul
I'm not going to be home for a couple of days, but when I get back I'll measure my Colt gas key and post the info here.
That is a plan, but I would wait for a dimension test first.
It would suck to spend $51, and then find out that the whole RRA 9mm carrier was taller -- right?
You're right. Its more of a range toy that a serious fighting tool I'm in not real hurry to fit the Gas Buster. I do want to make it right though.
I'll measure RRA key in the meantime.
...and yet my Hahn dedicated has creeped up under F/A fire just enough to create drag on my carrier. :eek:
How is that possible being that the dedicated Hahn is held under the guns factory bolt hold open device ? :confused:
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.