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Posted: 4/7/2011 8:55:50 PM EDT
I've exhausted my knowledge and internet searching. After reading everything I can find on AR15 and net, I now must ask the experts.

A year ago I purchased a used 9mm AR. My understanding was the gun was used in 3 gun, reliable and good to go. Well I have not had the best luck with this gun. When I first took it out to the range with factory 115gn Fedral FMJ it would FTE while loading the next round every 4th or 5th round. (stove pipes, cases backwards on top of the new round, etc) Figured it needed hotter ammo, so I started reloading for the gun.

Reloads were hit and miss. I'd have the same FTE every 4 or 5 rounds. Upon reaching the max load data for TiteGroup, I decided maybe something else is the problem as the rounds are hot. *NOTE* I am not seeing any case damage at the current load. I do have brass discoloring of the brass due to the blow back design of the AR but not from my Glock 17 or 26.

I was told the FCG was DPMS's, but I'm not sure.
http://www.jessereich.com/OSA/9mm/fcg.JPG

Originally the gun had a HANN Top Loading Mag block installed. Upon inspecting, the ejector appears to be bent to keep it in the bolt.
http://www.jessereich.com/OSA/9mm/hann_ejector.JPG

http://www.jessereich.com/OSA/9mm/hann_ramps.JPG

I do not believe it had a 9mm Heavy Buffer (the buffer WAS heavier then a stock RRA 5.56 buffer), however it did have a shorter spring then the rest of my rifle lowers. This is mil-spec buffer tube.
http://www.jessereich.com/OSA/9mm/buffersprings.JPG

The top buffer spring came in the gun, I've since changed to the lower buffer spring with RRA AR-15 take off buffer.

The gun came with a Ramped Bolt, but I don't know who made it.
http://www.jessereich.com/OSA/9mm/rampedbolt.JPG

All should be good. Too bad it isn't.

I decided I would start trying different know issue point to see if I could get it dump a full 33rd mag with out a problem.

First I replaced the buffer spring with the longer spring. I then added a new unramped bolt and finally a new bottom loading adjustable magwell block.

http://www.jessereich.com/OSA/9mm/unrampedbolt.JPG
http://www.jessereich.com/OSA/9mm/magwell_ejector.JPG
http://www.jessereich.com/OSA/9mm/magwell_ramps.JPG


Results: nothing has changed for the good or the bad. The gun will still have times of great success with both factory and relaod as well as continual FTE's with both types of ammo. All of my Mags are C-Products, 20 & 33 with black and orange followers. Regardless I don't see any major change in the operation of the gun.

The only thing that provides 100% reliability is if I load just one round at a time in a Magazine. It will fire and eject each round every time. Put two rounds and I have a 50-50 chance of it ejecting the first round and loading the 2 round.

Go with 5 or more rounds and it is hit and miss for success.

So, what do to next? I built my neighbors 9mm AR with a RRA lower, RRA 2-stage trigger, Unramped Bolt and bottom loading Magwell mag block. His gun is 100% reliable... aside from the Trigger, mine should be too!

I humbly submit my problem for your help and suggestions!

––Jesse
Link Posted: 4/7/2011 9:39:51 PM EDT
How's your extractor?
Link Posted: 4/7/2011 9:46:39 PM EDT
On the new un-ramped bolt, the extractor is sharp and strong. The original ramped bolt, the extractor does appear to have some visible wear.

I performed a test where I would hand operate the bolt via the CH with both bolts. I found the original ramped bolt didn't "grab" a couple of rounds and therefore they did not get kicked out of the gun. When performing the test with the new BCG, all of the rounds were properly ejected from the gun. This was a manual test.

Link Posted: 4/7/2011 9:58:55 PM EDT
Shot in the dark here, but on the pic of your new bolt, there is alot of wear on just one side. Just before the hammer opening. Do you have the height correct on the new adapter? You could also try replacing the ejector in the old adapter and using the new bolt to see if the problem still occurs.
Link Posted: 4/8/2011 2:50:19 AM EDT
The problem you describe is far more commonly related to the ejector than anything else.  First the ejector must be at the right height as determined by the position of the block. With a top loading block you need to make sure the top of the ejector is almost touching the underside of the bolt's ejector channel.  With a bottom loading block, you have a two-part adjustment issue; first the block has to be at the right height to feed, then the ejector has to be properly positioned.

It isn't clear how you did your part swapping.  Always change only ONE thing at a time to avoid missing what change made what difference.  Sorry I can't give you a simple "here's your problem!" answer.
Link Posted: 4/8/2011 7:31:33 AM EDT
Im guessing ejector too....most of the time with ejection problems, thats the culprit.  Mine drove me nutz trying to tailor reloads to work properly....I'm damned lucky I didn't blow the thing up, I worked some pretty hot loads thinking it needed it.  The ejector needs to ride as close to possible to the side of the bolt and to the top of the bolt.  Touching can cause it to short stroke, from the increased drag on the bolt when it cycles, so bend carefully and in small incriments.  Once u have the ejector tuned right, it should work for ya.  The best way to check ejector to bolt clearance is to partially pull the bolt to the rear, look thru the magwell and look up into the receiver, you should be able to see the face of the bolt and where the ejector is riding.  Once I had both mine and my brothers tuned properly, all ejection problems went away in both guns.....we were on the verge of scraping the whole 9mm idea.....glad I didn't!
Link Posted: 4/8/2011 7:53:42 AM EDT
Also, do you have access to any Metalform mags? I noticed you only had C Products and trying a different mag might give you different results.  I also agree with the above post of only changing one thing at a time for a better control group when testing. Good luck.
Link Posted: 4/8/2011 8:35:02 AM EDT
Quoted:
Also, do you have access to any Metalform mags? I noticed you only had C Products and trying a different mag might give you different results.  I also agree with the above post of only changing one thing at a time for a better control group when testing. Good luck.


^This^.......you should have tried different mags before changing anything.  What mags did the person you bought it from use?
Link Posted: 4/8/2011 9:45:24 AM EDT
Thanks for comments...

When I purchased the gun it came with an assortment of cProducts magazines in 20&33 rds. So when I ordered extra, I ordered the same brand.

To make sure I am using the correct terms:

Ejector is on the Mag Block

Extractor is on the bolt.

If that is correct, the Extractor looks worn on the Ramped bolt that came with the gun. The Hahn Ejector has been bent to ride close to the bolt and the bolt does not show signs of scraping on the Ejector.
-New Extractor for original bolt needed

The new magwell block can be adjusted to drag the bolt by inserting it to deep in the lower receiver, I've tweaked it a little and will try again in small adjustments to the ejector riding as close as possible without dragging.

I will do my best to try new magazines, 9mm AR's are in the area, but I don't know anyone who has one with a different type of magazine.

I can't go to the range until Saturday morning, but I will report back with photo's on the results.

Thank you so much!
Link Posted: 4/8/2011 2:26:58 PM EDT
Quoted:
Im guessing ejector too....most of the time with ejection problems, thats the culprit.  Mine drove me nutz trying to tailor reloads to work properly....I'm damned lucky I didn't blow the thing up, I worked some pretty hot loads thinking it needed it.  The ejector needs to ride as close to possible to the side of the bolt and to the top of the bolt.  Touching can cause it to short stroke, from the increased drag on the bolt when it cycles, so bend carefully and in small incriments.  Once u have the ejector tuned right, it should work for ya.  The best way to check ejector to bolt clearance is to partially pull the bolt to the rear, look thru the magwell and look up into the receiver, you should be able to see the face of the bolt and where the ejector is riding.  Once I had both mine and my brothers tuned properly, all ejection problems went away in both guns.....we were on the verge of scraping the whole 9mm idea.....glad I didn't!


The Colt style 9mm will cause a great deal of head thumping. you've outlined everything I've went through on Colt style set up's. My 2 run very well now. It was great growing pains years back and lord knows I have more 9mm shit around here than anyone with sense would!

I've had a great better deal of luck with Olympic 9's and Sten mags. Sten's suck to load,even with the tools.

I'd always thought that little shit wire ejector would fail in an Olympic 9mm upper. After 15 years and loosing count I was wrong. I still have 4 spare ejectors. LOL.

Link Posted: 4/10/2011 3:02:03 PM EDT
Range Update

So I was able to visit the range this weekend and work with the 9mm AR... It was a positive experience and I was able to successfully put 200 rds of ammo down the pipe. This was factory WWB, Federal, Remmy, in addition to my special reloads. All few nicely and the gun ran very well.

What did I do?

1) Well I weighed all of my buffers and found one was about 3oz and the other was much heavier. I couldn't be sure since my scale can't go above 3oz. From internet searching I found a buffer spacer might be needed, and could only cost $1.75 in quarters put down the buffer tube. (http://suburbansdomain.blogspot.com/2010/06/175-solution-to-9mm-ar-15-problem.html)

2) Reviewed both BCG's and cleaned them both VERY WELL! I still need to replace the extractor on the Ramped bolt, but it performed very well today.

3) Magwell - Took the new bottom loading magwell, with a hammer, I worked the ejector so it would ride very close to the bolt, but did NOT touch the bolt. I then adjusted the placement of the ejector so it was sure to hit the center of the brass.

4) Mags - I had a variety of new and old C-Products 32 rd (Version 1 & 2) Magazines. I did not have to do anything for these to function properly.

5) GRIP on the gun! I believer this was the most important and impacting change I made. I typically shoulder the weapon with the support hand on the Magwell and Magazine. For 5.56 magazines this is not an issue. I found that by moving my had to the forearm of the weapon and ensuring that I am not pushing, pulling or impacting the placement of the magazine, the gun worked properly. This was an instance change in performance.

After a little working, it went well. Taking what I had learned, I was able to successfully drop all the ammo I could find down range. Now that the ejector is in place, I feel good with the weapon. I look forward to my next trip.

Thank you all for your help and suggestions!
Link Posted: 4/11/2011 2:37:49 AM EDT
My 9mm build had many of the same issues you are experiencing.  Here is what I did to fix the problems. I had a c-products mag well adapter which is junk so I swapped it for a Hahn (top install) mag well adapter.   I had a couple of c-product mags but had FTF issues continued with both of them after the mag well swap. Now I use only the  metalform mags which are expensive but prove to be very reliable. Ok, heavy buffer installed. I use the standard spring.  In your photos it looks like your extractor is bent.  Not sure how this happened but it may be dragging on the carrier.  I doubt ammo is the problem, mine will fire any ball ammo I put into it.   Hang in there and  try one thing at a time and you'll figure it out.  Since installing these fixes in my 9mm AR I haven't had any failures.  Another thing with these 9MM ARs is the direct blow back operation they tend to be very dirty so you have to keep it clean.  I fired 500 rounds through mine in one outting with no problems but not too sure how long it would remain reliable without cleaning.  Good luck.
Link Posted: 4/23/2011 5:49:40 AM EDT
when you say " standard spring  " do you mean a .223 buffer spring ?
Link Posted: 4/23/2011 11:32:43 AM EDT
First, make sure your extractor is lining up correctly with your bolt, this could cause FTE problems. It may need bent over a little, mine did on my Hahn bottom mag block. I had (5) new CP 32rd mags that I had all kinds of problems with, even after adjusting the extractor, got rid of all of them and kept my 32rd Metalforms and 25rd RRA modified UZI mags. Hasn't missed a beat since.

teamroper

edit....sorry, didn't read the whole thread, sounds like you got it figured out.
Link Posted: 5/2/2011 9:49:25 AM EDT
I would just echo the ejector comments, that wa the problem with my Spikes and now it is great.

Also who would run a 9mm Ar in three gun? Make no sense really.
Link Posted: 5/2/2011 5:23:45 PM EDT
Quoted:
Also who would run a 9mm Ar in three gun? Make no sense really.


Why do you say this?

dzc

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