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Posted: 9/5/2010 9:55:36 PM EDT
I was at the range awhile back putting the first hundred or so rounds downrange with my new DSA AR. After lurking on this site for awhile, I decided to get a BCM BCG.

Anyway, while out on the range I experienced a double feed and a malfunction I do not know the term for. Basically the brass was wedged between the charging handle and the BCG. The buffer spring tension prevented me from pulling the CH back and the malfunction required a rod to pry out the brass. Both malfunctions occurred with D&H mags with Magpul followers that I got from Bravo Company. I do not know if it was the same mag.

P-Mag was 100%. Is this probably mag related? Also, any advice on how to clear that malfunction more easily would be appreciated.
Link Posted: 9/6/2010 7:05:56 AM EDT
Most problems of this kind are mag related ... every double feed problem I have had or seen was either related to the mags or people pressing against the mags (using the magwell as a handhold) while they were shooting. Now the other problem your describing "brass was wedged between the charging handle and the BCG" ... so it's a spent casing that didn't eject and got wedge into the CH while the BCG was trying to feed another round?
Link Posted: 9/6/2010 8:43:15 AM EDT
Originally Posted By Gatorhunt:
Most problems of this kind are mag related ... every double feed problem I have had or seen was either related to the mags or people pressing against the mags (using the magwell as a handhold) while they were shooting. Now the other problem your describing "brass was wedged between the charging handle and the BCG" ... so it's a spent casing that didn't eject and got wedge into the CH while the BCG was trying to feed another round?


That's exactly right. The BCG went to the rear, and I guess before the casing was ejected out the ejection port, the BCG started moving forward catching the case between itself and the charging handle. The case trapped the BCG in the rearward position, which made pulling on the CH extremely tough because of the buffer spring tension directed forward.
Link Posted: 9/6/2010 8:58:03 AM EDT
Link Posted: 9/6/2010 9:42:03 AM EDT
Originally Posted By BDynamite:
Originally Posted By Gatorhunt:
Most problems of this kind are mag related ... every double feed problem I have had or seen was either related to the mags or people pressing against the mags (using the magwell as a handhold) while they were shooting. Now the other problem your describing "brass was wedged between the charging handle and the BCG" ... so it's a spent casing that didn't eject and got wedge into the CH while the BCG was trying to feed another round?


That's exactly right. The BCG went to the rear, and I guess before the casing was ejected out the ejection port, the BCG started moving forward catching the case between itself and the charging handle. The case trapped the BCG in the rearward position, which made pulling on the CH extremely tough because of the buffer spring tension directed forward.


But this doesn't happen with the P-mags at all?

Do the ejector cleaning, function test with one round and O-ring upgrade that Dano523 is talking about ... that will eliminate some of the possibilities. If the BCG isn't locking back on the last round then the rifle is short stroking and could be a gas system problem.
Link Posted: 9/6/2010 9:48:42 AM EDT
[Last Edit: 9/6/2010 9:50:17 AM EDT by BDynamite]
Originally Posted By Dano523:
Since you stated BM BC, you need to confirm that the key bolt are still tight (37inlbs) and the rifle is full stroking to begin with.

With only a single round in a mag, charge and fire that round, and confirm that the bolt is locking back on the bolt catch.


If the bolt does lock back, and the problem is a fired case, and live case being in the action with the jam, then the extractor is dropping the spent case off the bolt face before end of rearward stroke, and increasing the spring tension via a #60 O ring around the extractor spring may solve the problem. Also could be that the ejector is binding up in the bolt face channel, and it need to pulled and clean. Lastly a possable problem could be that the bolt face is retracting back past the back edge of the ejection port, and the case is being defected back in off the back edge of port.


If the problem is only live rounds in the action alone and the rifle is full stroking, then that is all mag.


1. If you mean Bushmaster bolt carrier, it's not. It's a Bravo Company BCG

I'll try with P-mags some more I guess. If I have the same problem it must be the extractor or the ejector. If it is an ejector or extractor problem, would heavier buffers/springs help? Thanks

Edit: Bolt locks back perfectly with the P-Mag I had, everytime I used it.
Link Posted: 9/6/2010 10:05:45 AM EDT
Originally Posted By BDynamite:
Originally Posted By Dano523:
Since you stated BM BC, you need to confirm that the key bolt are still tight (37inlbs) and the rifle is full stroking to begin with.

With only a single round in a mag, charge and fire that round, and confirm that the bolt is locking back on the bolt catch.


If the bolt does lock back, and the problem is a fired case, and live case being in the action with the jam, then the extractor is dropping the spent case off the bolt face before end of rearward stroke, and increasing the spring tension via a #60 O ring around the extractor spring may solve the problem. Also could be that the ejector is binding up in the bolt face channel, and it need to pulled and clean. Lastly a possable problem could be that the bolt face is retracting back past the back edge of the ejection port, and the case is being defected back in off the back edge of port.


If the problem is only live rounds in the action alone and the rifle is full stroking, then that is all mag.


1. If you mean Bushmaster bolt carrier, it's not. It's a Bravo Company BCG

I'll try with P-mags some more I guess. If I have the same problem it must be the extractor or the ejector. If it is an ejector or extractor problem, would heavier buffers/springs help? Thanks

Edit: Bolt locks back perfectly with the P-Mag I had, everytime I used it.


If it's a Bravo Company then the extractor is probably GTG ... test the ejector to make sure it isn't binding on the bolt somewhere.

The rifle could also be slightly over gassed causing the case to thrown into the inside edge of the ejection port and then bouncing back into the receiver ... in that case a heavier buffer might solve your problem.
Link Posted: 9/6/2010 11:31:51 AM EDT
[Last Edit: 9/6/2010 11:34:51 AM EDT by Dano523]
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