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Posted: 5/18/2009 7:14:38 PM EDT
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I went to the range today and experianced several double feeds. I used P Mags and a USGI steel mag. Happened with both types of magazines. I was using Federal XM193 ammunition. I have never had double feed problems before. Also, the bolt failed to lock back after the last round a couple of times. What causes this and how can I fix it?
Thanks!! |
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my bro is having the same problems with us and p mags.... im gonna detail it polish the feed ramps, run a pipe cleaner through the gas tube and shoot gun scrubber down the gas key, and check the gas rings.
you know how the check the rings? place the bolt in the carrier, grab the tail and let the bolt hang down. if it falls out, time to replace the gas rings. also, the key screws might be tight, check to make sure the key itself is tight and that your buffer and tube are clean and lubed. |
| Everybody seems to be saying "gas problem", but how would that cause the bolt to strip two rounds off the top of the mag? This sounds more like a weak mag spring issue - the recoil causes a round to pop out of the mag, and then the bolt picks up another one. I've seen it happen with old USGI mags, hard to believe it'd be happening with a Pmag. |
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Quoted:
Everybody seems to be saying "gas problem", but how would that cause the bolt to strip two rounds off the top of the mag? This sounds more like a weak mag spring issue - the recoil causes a round to pop out of the mag, and then the bolt picks up another one. I've seen it happen with old USGI mags, hard to believe it'd be happening with a Pmag. My experience with double feeds is that it is usually weak springs. |
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Quoted:
Quoted:
Everybody seems to be saying "gas problem", but how would that cause the bolt to strip two rounds off the top of the mag? This sounds more like a weak mag spring issue - the recoil causes a round to pop out of the mag, and then the bolt picks up another one. I've seen it happen with old USGI mags, hard to believe it'd be happening with a Pmag. My experience with double feeds is that it is usually weak springs. This. Imagine it goes away when you change mags... |
| Eric802, I know OP said it happened after ejection... admit it's a head-scratcher. I will say I was fooled w/my problems in thinking extraction was ok - it would rock and roll and eject them forcefully then JAM suddenly with the double feed. According to several in arfcom, a weak extractor spring or bad extractor can let the case go before it leaves the rifle, then the spring on the ejector unloads so the ejector can't do it's job, so the spent case will just ride down with the new round coming in and they'll both cram together on the barrel extension. OP might give it a try... cheap, quick... o-ring is easy to put on. Solved my double feeds. |
| I sent the rifle back to LMT after talking with one of their reps. They fired over 100 rounds through it without a problem. After firing and inspecting it, they could not find anything wrong. Maybe it was a mag issue. The mags that I used were a USGI aluminum, and two brand new PMAGS. I guess it is GTG now. Also, the people at LMT were great to deal with and very helpful. Great Company. |
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Quoted:
Eric802, I know OP said it happened after ejection... admit it's a head-scratcher. I will say I was fooled w/my problems in thinking extraction was ok - it would rock and roll and eject them forcefully then JAM suddenly with the double feed. According to several in arfcom, a weak extractor spring or bad extractor can let the case go before it leaves the rifle, then the spring on the ejector unloads so the ejector can't do it's job, so the spent case will just ride down with the new round coming in and they'll both cram together on the barrel extension. OP might give it a try... cheap, quick... o-ring is easy to put on. Solved my double feeds. No, it solved your dropped extraction issue. A double-feed is two live rounds trying to occupy the chamber at the same time. |
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Quoted:
Eric802, I know OP said it happened after ejection... admit it's a head-scratcher. I will say I was fooled w/my problems in thinking extraction was ok - it would rock and roll and eject them forcefully then JAM suddenly with the double feed. According to several in arfcom, a weak extractor spring or bad extractor can let the case go before it leaves the rifle, then the spring on the ejector unloads so the ejector can't do it's job, so the spent case will just ride down with the new round coming in and they'll both cram together on the barrel extension. OP might give it a try... cheap, quick... o-ring is easy to put on. Solved my double feeds. Ahh, I see the confusion now. I believe your malfuncion would be more accurately called a "failure to eject," as the rifle is trying to feed a fresh round along with a spent (but not properly ejected) case. The OP's problem is two FRESH rounds trying to feed. Magazine related most likely Tex78 |
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