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Posted: 9/6/2010 7:05:56 AM EDT
[#1]
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?
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Posted: 9/6/2010 8:43:15 AM EDT
[#2]
Quoted:
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. |
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Posted: 9/6/2010 8:58:03 AM EDT
[#3]
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. |
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Posted: 9/6/2010 9:42:03 AM EDT
[#4]
Quoted:
Quoted:
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. |
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Posted: 9/6/2010 9:48:42 AM EDT
[#5]
Quoted:
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. |
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Posted: 9/6/2010 10:05:45 AM EDT
[#6]
Quoted:
Quoted:
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. |
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Posted: 9/6/2010 11:31:51 AM EDT
[#7]
If the bolt face is stopping before the back of the ejection port correctly (1/4" to 3/8" between the face of the bolt and back of ejection port, and just pull all the way back on the CH to see), then there is not way that the spent case should make contract with the back of the port.
So if the above is correct, then either short stroking, extractor spring weak, or ejector binding up in the channel. To add, if this problem is only happening when you use the mag as a hold point, could be that there is enough slop in the well to allow the mag to be end canted enough to slow down the B/C stroke, and cause short stroking. |
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