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View Full Version : UPDATE: 11/2/09, 9mm AR Build Problems, C Products Mags?


dot429
11-02-2009, 1:20 AM
Greetings all,

Some of you may remember my 9mm RRA AR build:

http://s-prefix.smugmug.com/Hobbies/9mm-AR-1/9mm-AR-068/674306021_d7cwY-L.jpg

I really love the rifle. I was disappointed that the RRA 9mm 10 round mag did not lock the bolt back after the last shot, so I ordered some C Products mags based on some input here and other places in the Ether.

It turns out that ever since I started running the C Products mags, I'm getting double-feeds and FTEs, sometimes, both at the same time. A few times, the jams were so bad that I couldn't pull the charging handle back far enough to lock the bolt back because the FTE'd brass went back into the action... geez!

What gives? Are C Product mags junk? Or, is there something else going on? I never had one single failure with the RRA mag, but didn't like the fact that it didn't lock the bolt back. I've tried running the rifle with a spacer in the buffer tube and w/o, I've tried all sorts of ammo, I've marked the 4 C Product mags, but I get inconsistent FTEs and double-feeds with all of them with or without the spacer and in spite of ammo.

Any thoughts would be appreciated. Like I said, I really love the rifle, but constant jams are no fun. I'm going to call C Products and RRA to find out more.

Thanks in advance if you have some valuable input.



UPDATE 11/2/09:

I just spoke with Sarah at C Products, their customer service is GREAT!!!

She explained that the mags I received were the older style mags and that they have since made some engineering changes to the mags so that they will work w/the RRA conversion block.

C Products is sending me a pre-paid return label and is going to send the newer/correct replacements a.s.a.p.

That's great customer service in my book!

Thanks to all for the input.

redcliff
11-02-2009, 1:46 AM
Common problem; this is from C-products web site:
"If purchasing a 9mm magazine for use in a Rock River Rifle, you will need to adjust the magazine block .015-.020 lower to function properly in this platform. "

I'm making the assumption that you have a Rock River magazine block in your RRA rifle?

ghost
11-02-2009, 2:19 AM
i`m currently running a c-products mag block with c-products mags in my pistol build and it functions flawless.

Desert_AIP
11-02-2009, 7:35 AM
With any 9mm using any mag block and magazines you have to make sure the ejector is as close to the bolt as possible.
There isn't alot of room in the groove in the bolt for the ejector.
If the ejector is not all the way up in that groove, there is not much area for it to act on the rim of the extracted case.
It can miss the case and cause a jam.

Once the mag block is set up correctly to engage the magazine, look at the ejector position in the bolt, through the ejection port.
You shouldn;t see much if any gap between the top of the ejector and the bottom of that groove.

I was getting the same FTF/FTE problems you describe.
I had to bend the ejector up toward the bolt about 3mm to close the gap.

After I did that it runs 100%.
I'm using CProducts magazines with a Hahn dedicated block.
But this should work with your combination.


Quoted from similar troubleshooting talk on ARFCOM
Originally Posted By GHPorter:
The CProducts follower is at a much steeper angle than Uzi magazines' and Promags copy the Uzi's follower. The issue is not that the magazine is different, just that it needs to sit in a different spot to feed properly-and your ejector needs to be properly positioned. With that steep angle, CProducts magazines need to be set a bit lower in the gun, which you CAN do with any adjustable magazine block. I keep my RRA block as low as it will go in the mag well, and my CProducts magazines work great.


Originally Posted By GHPorter:
It's the ejector. The ejector MUST BE as close as possible to the bolt to function properly, otherwise instead of the ejector kicking the empty case out of the gun, the fresh round from the magazine pushes it off the bolt and the empty gets stuck in the upper. This happens with ANY 9mm carbine magazine.

The ejector is small, and the space in the bolt for it is even smaller. The face of the ejector must be parallel to the bolt face, and the side of the ejector must all but scrape the groove in the bolt, or it will miss the empty case completely. See how close yours gets, and I'll bet you'll be surprised at how tiny the space is, and how far your ejector is from that space.

Originally Posted By kevins_garage:
Not much tuning to do - play with the height of the block if you have to, check/adjust the extractor tension, and adjust the ejector is about it.

Look through the ejection port as you pull the charging handle back and try to position the front of the bolt face right at the ejector - make sure the tip of the ejector is as high and tight to the center of the bolt as possible so it makes as much contact with the spent case as possible. Green dot on the pic below.

http://img.villagephotos.com/p/2004-12/908913/9mm%20bolt.jpg
If your ejector is not in the green position, adjust it. I have seen some guns with Hahn blocks and Metalform/Uzi mags run 100% even though the position of the ejector was closer to red or blue than green. I have not seen any run if the ejector was near the yellow.

dot429
11-02-2009, 12:31 PM
Common problem; this is from C-products web site:
"If purchasing a 9mm magazine for use in a Rock River Rifle, you will need to adjust the magazine block .015-.020 lower to function properly in this platform. "

I'm making the assumption that you have a Rock River magazine block in your RRA rifle?

Thanks. I take it that I need to adjust magazine block.

Does anyone have pictures of exactly how to "adjust the magazine block .015-.020 lower" ?

:confused:

Desert_AIP
11-02-2009, 12:41 PM
Loosen the allen screw, slide it down in the magwell and re-tighten.

I would bottom it out and start from there:
Loosen the block.
Remove the magazine if installed.
Leave the magcatch in place so it is in the slots of the magazine well and mag block.
Slide the magblock down until it catches on the top of the magcatch.
Re-tighten the mag block allen screw.
Make sure the mag catch still funtions properly, i.e. moves in the slot easily.

jchen76@gmail.com
11-02-2009, 12:43 PM
Did you buy the mags from cproducts directly or through vendor? If cproducts, contact them and they should send you new ones. If through vendor, you may have bought a 1st gen magazine with bad followers. I have the same exact setup. During my 1st range trip, my Uzi modified magazines were great, no issues. 2nd range trip with 1st gen cproduct magazines was terrible, could get only 2 shots of before issues. Once c-products sent me new magazines, no issues. Did not change the mag well setup or anything. Was shooting combination of Wolf and Win WWB.

dot429
11-02-2009, 12:54 PM
Update:

I just spoke with Sarah at C Products, their customer service is GREAT!!!

She explained that the mags I received were the older style mags and that they have since made some engineering changes to the mags so that they will work w/the RRA conversion block.

C Products is sending me a pre-paid return label and is going to send the newer/correct replacements a.s.a.p.

That's great customer service in my book!

Thanks to all for the input.

D53
11-02-2009, 12:59 PM
thats great that they are willing to swap out the old mags for the newer version plus pay for shipping both ways.

tay
11-03-2009, 10:50 AM
I had similar problems with my AR15 9mm built with FTE and 'stove piping'.

I tried everything from adjusting the RRA mag block height, new CProducts mags, cleaning and other fixes.

Finally I 'adjusted' ejector and now my AR15 9mm is working great.

The adjustment is by slightly bending the ejector:

http://www.m4carbine.net/showthread.php?p=479910

http://dvctargets.com/Misc/Images/fa-ar-9mm-ejector_tweak.jpg

I bended my just enough as mentioned in the above reply.

DREADNOUGHT78
11-03-2009, 10:55 AM
Good info guys.And great customer service from C-products. I just got the same mag block for a buddies build.