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Posted: 8/3/2009 9:28:20 AM EST
I need a little help from the experts.

I seem to be having a worsening double feed issue with my AR. This past weekend I had multiple double feeds with the first bullet attempting to chamber, and the following bullet coming out of the mag and catching the first bullet, preventing the first bullet to chamber. I have had this problem before, but usually only once a range trip.

This happened with 3 different 30 round Pmags.Also, everytime this happened, there was only 1 bullet left in the magazine. I thought double feeds were magazine related, but this happened with three different magazines.

The rifle is a DPMS with M4 feed ramps, and I was shooting 55 grain Brown Bear.

Please help.





Link Posted: 8/3/2009 9:51:38 AM EST
I'm sorry that you're having problems

Do your PMags fit tightly in the magwell of your rifle?
Link Posted: 8/3/2009 10:11:08 AM EST
Resting the rifle on the magazine like a mono pod can cause double feeds.
Link Posted: 8/3/2009 10:15:13 AM EST
[Last Edit: 8/3/2009 10:17:44 AM EST by LIL-COMMANDO]
Are you saying; when a round is fired the empty cassing is not ejecting and the live round is trying to feed from the magazine? Or you fire the empty ejects and two live rounds try to feed? Double feeds are magazine related so try another magazine and use regular 5.56 or 223 ammo and not that steel case stuff. First try brass style ammo in those Pmags to see what happens.

Oh you did say two live rounds feeding at same time, got it..
Link Posted: 8/3/2009 11:26:48 AM EST
Originally Posted By StewartTR:
Resting the rifle on the magazine like a mono pod can cause double feeds.


According to the Army Marksmanship Training Unit at Ft. Benning, who tested and evaluated this, it is a myth. The Army now encourage troops to rest their rifle on the mag while qualing to create a more stable platform.
Link Posted: 8/3/2009 12:11:57 PM EST
[Last Edit: 8/3/2009 12:13:14 PM EST by MikefromTX]
I'm trying to picture this:

The bolt comes forward and strips off a live round, then *something* strips a second round from the mag??? The only "something" that could do that would be the underside of the bolt carrier, isn't it?, and it's smooth so it won't do that.

Is it possible the lip of the carrier just below the bolt itself can be catching the second round and stripping it as well? That would be bizarre.

Seems to me the mag is improperly releasing the second round somehow. And since you say you've tried 3 different mags - and it's always when there's only one round left in the mag - it almost HAS to be a mag issue, I'd think.

.
.
Link Posted: 8/3/2009 1:29:45 PM EST
Sorry for the confusion

The previous round is being ejected properly, but when the next round tries to chamber, the one bellow it comes up the feedramp and prevents it from chambering, and the bolt isn't fully closed. I know this sounds strange, but when it jams like this, I pull the mag out and the second round is purched at a 45 degree angle with the tip of the bullet at the end of the feedramp blocking the bullet from chambering.

I'm not supporing the gun on the magazine, and the mags fit comfortably (not tight or loose) inside the magwell.

When I first bought the gun, it never did this, but has been happeing more and more.

Thanks for the replies, and any further suggestions.
Link Posted: 8/3/2009 4:04:16 PM EST
I had FTF and 2x feed w/ Pmag 20s. Realized that the rounds were canted upward. Dress-right-dress the round = no problemo.
Have since converted.
Link Posted: 8/3/2009 5:06:47 PM EST
Originally Posted By troy808: Dress-right-dress the round = no problemo.


Thanks for the reply, but what does this mean.
Link Posted: 8/3/2009 6:53:25 PM EST
[Last Edit: 8/3/2009 6:58:48 PM EST by GearHead_1]
This description is odd to say the least. I know you mentioned trying multiple PMags, did you try any GI mags, if not could you? I've seen a situation that was similar one time. The build had used an O-Ring on the front upper stud of the receiver (I've seen these work fine). This rifle had a very fat O-Ring, to the point where it cocked the magazine oddly. I would not have picked this up had I not inserted a mag several times. It felt like it had an extra click when I installed the mag. It was actually grabbing the mag when it went by. I can't tell you how the bolt stripped two rounds but oddly enough that was then end result. Installing a thinner O-Ring made the problem disappear.
Link Posted: 8/3/2009 7:15:38 PM EST
Have you tried different ammo? Double feeds are usually mag related, but I would try some different ammunition.
Link Posted: 8/3/2009 7:54:16 PM EST
[Last Edit: 8/3/2009 7:56:32 PM EST by troy808]
Originally Posted By Peart2112:
Originally Posted By troy808: Dress-right-dress the round = no problemo.


Thanks for the reply, but what does this mean.



Sorry for the ambiguity
Dress-right-dress is a term used to align all the troops in a row, eg: for inspections, etc

Found this picture somewhere.
Hope that this may help.....



I have "heard" that the bolt either gouges the case and jams the round as it tries to chamber,
or just scratches the bleep out of the round and results in FTF.
Anywayz, for proper operation, orientation of the rounds should be as in the 30, versus the 20.
Ensuring that the rounds are "proper" should be GTG

Easy enough check before shooting, if not, disregard.

Personally, I haven't seen this in USGI mags
Link Posted: 8/3/2009 8:02:44 PM EST
Just realized:
Peart2112,......as in Neil?
Link Posted: 8/4/2009 5:23:24 PM EST
Originally Posted By troy808:
Originally Posted By Peart2112:
Originally Posted By troy808: Dress-right-dress the round = no problemo.


Thanks for the reply, but what does this mean.



Sorry for the ambiguity
Dress-right-dress is a term used to align all the troops in a row, eg: for inspections, etc

Found this picture somewhere.
Hope that this may help.....

http://i153.photobucket.com/albums/s231/rush2112-/AR15/Pmag_ammo_sm.jpg





I have "heard" that the bolt either gouges the case and jams the round as it tries to chamber,
or just scratches the bleep out of the round and results in FTF.
Anywayz, for proper operation, orientation of the rounds should be as in the 30, versus the 20.
Ensuring that the rounds are "proper" should be GTG

Easy enough check before shooting, if not, disregard.

Personally, I haven't seen this in USGI mags



Interesting you mention the case getting gouged by the bolt. This does happen on the second round in the double feed. Guess I'll have to pay more attention to how i load my rounds, or try some USGI mags. Thanks for the info and pic. This has been very helpfull.



Link Posted: 8/4/2009 5:24:40 PM EST
Originally Posted By troy808:
Just realized:
Peart2112,......as in Neil?



Yes. Neil Peart is a God.

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