View Full Version : Feeding Problems with 9mm AR

07-12-2007, 12:04 PM
After a few weeks of waiting, I finally got my hands on a promag magazine (32/10) my friend brought for me from NV.

My setup is as follows:

RRA 9mm Upper
RRA 9mm Hammer
RRA Magazine Bock
Stag Lower Receiver
Stag LPK
Misc. tactikewl stuff

I inserted the Promag magazine into the RRA block and locked the button in place. I then proceeded to tighten that allen-screw on the bottom front of the mag block after everything was in.

I load ten rounds into the magazine and fire. After the first shot, the rifle jammed. I looked through the ejector port to discover the bolt halfway open and a 9mm round that's completely out of place and stuck in between the bolt and chamber. I eject that cartridge out, and the next round goes in. I fire, and the exact same thing happens again. Basically, every other round is jamming.

I was wondering what may be causing this? I have a lot of other friends running the exact same setup without any problems at all, so perhaps I need to start adjusting a few things here and there. Would adjusting the mag block work?

Anyone experience this?

07-12-2007, 12:22 PM
When I had my 9mm AR I made sure I had grabbed everything on the RRA 9mm manual. The parts I had that you didn't list makes me ask if you got the correct buffer and spring in the stock?

07-12-2007, 12:47 PM
Thanks for pointing that out, I forgot to mention that;

Yes, I do have the correct RRA 9mm buffer and spring inside the stock.

07-12-2007, 12:54 PM
I had the same problem with my AR15 9mm if I use some surplus ammo.

When I use the Walmart Winchester 9mm I never have a feed problem.

Can also be an issue with the magazine, hopefully when Cproducts comes out with the 9mm 10-round it would solve the mag issue.

07-12-2007, 1:17 PM
might wanna try leaving the allen screw loose untill you find the sweet spot for proper feeding then tighten up allen lock screw also it could be in the mag, pro mags are known for poor tollerances

07-12-2007, 2:46 PM
what kina ammo are you using? replace the promag dude..

07-12-2007, 3:47 PM
I'm using regular white box Winchester rounds.

I think I gotta play around with and tune the mag block b/c all my other friends' setups with their promag magazines have been working beautifully for a long time now.

I will eventually replace the magazine and mag block whenever they decide to get some 9mm AR mags available to the market.

Hopefully metroshot has some mags left still.

07-12-2007, 5:45 PM
I have 3 promags for my 9mm. They work great and catch the bolt. Make sure your magwell block is flush with the top level of the receiver. I use cheap CCI brass and the gun works fine. It even works with lead, unjacketed ammo. If your rifle continues to jam contact RRA. I have the same parts list you have with no issues at all.