Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Site Notices
9/19/2017 7:27:10 PM
Posted: 11/2/2005 11:09:08 PM EDT
Still having problems failing to eject with my homebuilt RRA 9mm.

After firing, the empty case is gets caught in the ejection port and bolt when feeding a new round. If it ejects, it barely clears the ejection port.

Tried 115gr and 124gr factory ammo. It ejects fine if there is no magzine in the magwell. Pulled the extractor and cleaned it (roll pin is tight), extractor holds loaded round, headspace is good, used lots of oil on bolt/buffer & spring, using Colt 32rnd mags. Bent/adjusted the ejector to get the point as close to the cutout in the bolt. All RRA parts.

barry
Link Posted: 11/3/2005 3:06:55 AM EDT
Darn -- I can't believe you still have that problem! Since I can't tinker with your 9mm I'm just making a guess but I still think that the magazine is up high enough to hit the rim of the round before it gets to the ejector -- this may be the reason the 9mm works with no magazine. I remember at one time I read that backing the mag-catch out a couple of turns actually let the mag sit a hair lower -- I've never tried this but since nothing else has worked maybe you should try it and see if it helps. It's kind of a shame that a good fix has not shown up for you here on ARFCOM after all this time -- I really wish I could be more helpful.
Link Posted: 11/3/2005 4:46:08 PM EDT
What (weight) buffer are you using?
Link Posted: 11/3/2005 9:55:07 PM EDT
I lowered the entire mag block with no improvement. I'll try to unscrew the mag catch, nothing to lose.

I have the black, short, heavy buffer.

I'll try other mags i.e. converted Uzi's and other Colt mags. Seems to be a problem with the mags or mag block or something since it works without a mag in it.

Thanks to all who offered suggestions, this is my first 9mm build (maybe last ). Have had excellent results with all of my 5.56/.223 ar's.

barry
Link Posted: 11/4/2005 12:25:48 AM EDT
Don't give up on 9mm ARs! Send it back to RRA or take it to someone who is experienced with these conversions. Any or all of these components could be a little off just enough to plague you into insanity. With good hardware and magazines they run extremely well....evidenced by the growing popularity, especially in the law enforcement arena.

Not that this is your FTE problem but you only need a drop of oil on each of the bolt rails and other contact areas......too much oil attracts residue and will quickly gum up your action. NEVER run dry.
Link Posted: 11/4/2005 9:30:19 AM EDT

Originally Posted By HI5-0:
Thanks to all who offered suggestions, this is my first 9mm build (maybe last ). Have had excellent results with all of my 5.56/.223 ar's.


FWIW, my 9mm AR is the only one that required any sort of noticeable break-in period. It took a few hundred rounds until it smoothed out, but now it runs like a clock. Stay with it!
Link Posted: 11/4/2005 9:22:45 PM EDT
Thanks for the encouragement, I hate to "fail" at things so I won't give up. It'll have to be put on the side for about a week as I will be going to Arizona to shoot my pistol

barry
Link Posted: 11/5/2005 5:11:40 AM EDT
Had the same problems here's what I did to fix...

First, knock out the extractor pin. If its a rolled up piece of metal, chuck it and replace with proper roll-pin. THIS IS A MUST!

Seconds, Chuck the black 9mm buffer and replace with an AR "H" (heavy) buffer.

Watch in slow motion as you pull the charging handle back with an empty round in the chamber. See if it makes and dislodging contact with either the next round in the mag or the mag itself. Adjust the block as necessary.

That should get you rolling.

Matt
Link Posted: 11/5/2005 6:10:43 PM EDT
[Last Edit: 11/5/2005 6:11:05 PM EDT by M4-TUNA]
Mine had problems at first it was due to Remington ammo it did not have the power to get my bolt to work right. Winchester white box worked fine and still does.OH my gun is all RRA parts.
Link Posted: 11/13/2005 7:25:27 PM EDT
If it works without a mag, the magazine /loaded rounds are slowing the carrier down as it moves to the rear, that's why the empties are just barely making it out. Maybe bad mags or improper / faulty mag block system.
Link Posted: 12/8/2005 9:14:55 AM EDT
Link Posted: 12/10/2005 10:01:51 PM EDT

Originally Posted By kavik:
If it works without a mag, the magazine /loaded rounds are slowing the carrier down as it moves to the rear, that's why the empties are just barely making it out. Maybe bad mags or improper / faulty mag block system.



Okay, I'm back.....shot it with modified UZI mags and it works much better. Empties are ejected about 4 feet and had one fail to eject out of 10 shots. Also discovered the UZI mags lock in the mag block easily with the bolt closed.

I put the COLT mag (another new one) back in and same failures to eject almost every shot. Noticed these mags need a firm tap to lock in the mag block when the bolt is closed.

Narrowing the problem down to mags and or mag block. Using all RRA stuff on this build. Would changing to a different mag block make it more reliable with the COLT mags?

If so, which mag block do I get?

Thanks for the help guys.

barry
Link Posted: 12/11/2005 6:32:13 AM EDT
The job of the mag block is to fill most of the void in the magwell so 9mm mag will fit, hold the ejector finger, and feed ramp.

Have you tried your stuff in/on a borrowed lower, could be possible your lower is out of spec in regard to mag catch placement via drawing/measures from the front pivot pin ?
Link Posted: 12/11/2005 5:10:40 PM EDT
[Last Edit: 12/11/2005 5:10:53 PM EDT by Scollins]
I've been having the same problem with my RRA 9mm. It is a "parts gun", but with good parts. I get the FTEj, where the spent case is trapped by the bolt.

Setup:
RRA midlength 9mm upper
RRA bolt
RRA 9mm buffer
RRA 9mm hammer
Hahn bottom load block
SNS Industries lower (worked perfectly as a 5.56 before I changed to 9mm.)
Colt 32 round mags with plastic followers
Approximately 500 round through the system
Ammo: Winchester 9mm NATO load (124 grain.) NOT 9mm LUGER, but 9mm NATO (with the cross.)

I haven't tried playing with it yet to fix it, but if I can't get it fixed, I'm going to sell of the parts and make the lower into something else......
Link Posted: 12/11/2005 5:45:08 PM EDT

Originally Posted By Scollins:
I've been having the same problem with my RRA 9mm. It is a "parts gun", but with good parts. I get the FTEj, where the spent case is trapped by the bolt.

Setup:
RRA midlength 9mm upper
RRA bolt
RRA 9mm buffer
RRA 9mm hammer
Hahn bottom load block
SNS Industries lower (worked perfectly as a 5.56 before I changed to 9mm.)
Colt 32 round mags with plastic followers
Approximately 500 round through the system
Ammo: Winchester 9mm NATO load (124 grain.) NOT 9mm LUGER, but 9mm NATO (with the cross.)

I haven't tried playing with it yet to fix it, but if I can't get it fixed, I'm going to sell of the parts and make the lower into something else......


I had similar problems with my setup, which was almost the same except for the Colt mags. I ran hot ammo through it with a lighter weight (M4 "H") buffer for a little while and that helped smooth things out a bit. I'm still going to get the bolt ramped when I get back though.
Link Posted: 12/11/2005 9:47:36 PM EDT
Just got back from Simunitions instructor training. Has anyone used their 20rd plastic mag for the AR conversion or know of anyone?

Their mag is the same exterior size as a 5.56 mag but made for the 9mm FX cartridge. Just a thought.

barry
Link Posted: 12/19/2005 4:00:22 AM EDT
Link Posted: 12/19/2005 4:21:57 AM EDT
My buddys 9mm did the same thing. Here is how we fixed his problem. The empty case would not clear the chamber. After looking at the mag block you could see that the emptys were only hitting one side of the ejector. I took a pair of linemans pliers and slightly bent the ejector toward the ejection port to the right. It runs 100% now. The emptys fly 5 to 10 feet! It only needed to be moved about 1/32 of an inch. If you go too far it will drag on the bolt. Hope this helps.

Good Luck.
Top Top