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Posted: 11/29/2009 12:07:17 PM EDT
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I have a complete upper from BM that FTF once every 60-90 rds, I'm running Pmags and mostly wolf 55 & 62 gr. ammo. It seems to run best right after a cleaning/lubing. The fired round is ejecting fine, but the next rd. out of the mag is only making it half into the chamber, at an angle.
I think the piston is in right, with the larger holes facing forward. Ejection is pretty good with cases going 8'. Any ideas? Before the wolf haters chime in,this also happens with standard XM193 ammo too |
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Is the BCG sliding ok when you pull it back by the charging and back forward again? It could be it's a bit too rough or the buffer tube, spring and buffer are the problem. First and foremost grease them up thoroughly all around with a light coat and a thicker coat at the bottom front of the buffer tube behind retaining pin. It will only help. Than a little grease on the bottom of the BCG where it slides on the receiver too. It could be Pmags too, never discount them. There good mags, but the rifle may not like them with good that right amount off between the upper and lower. They may not be seating right too with your lower. These are all just possibilities to take it as nothing more than that. Good luck. |
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Good point on the mags, just because they work fine in another AR does not mean they will work in this one.
The BCG is pretty well lubed and moving freely, I don't usually lube the buffer assbly. This is one of those infrequent stoppages that could be a bitch to diagnose. I plan on trying GI mags, checking every thing and giving it a full dose of lube and trying again. FWIW, this is my second BM piston upper...the first was a dog, FTF, FTE every 5-10 rds....sent it back to BM and they replaced it. I've got about 500 rds thru this one with no sign of "carrier tilt wear" |
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Quoted:
Good point on the mags, just because they work fine in another AR does not mean they will work in this one. The BCG is pretty well lubed and moving freely, I don't usually lube the buffer assbly. This is one of those infrequent stoppages that could be a bitch to diagnose. I plan on trying GI mags, checking every thing and giving it a full dose of lube and trying again. FWIW, this is my second BM piston upper...the first was a dog, FTF, FTE every 5-10 rds....sent it back to BM and they replaced it. I've got about 500 rds thru this one with no sign of "carrier tilt wear" You'll get it figured out I'm sure. There's no problem lubing the buffer assembly as it will only make it run smoother pushing the BCG forward for feeding. Not being a DI action the buffer assem. will actually stay very clean and the lube will be there doing it's job for a long time. I used Tetra grease on my POF's entire action (except the piston & block) and have never wanted to use something else after years of using it on all my weapons, but there are lots of good greases out there today. |
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