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Posted: 3/13/2011 7:49:32 PM EDT
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I've got a problem that I cannot seem to figure out.
New build, BCM 16" 410SS barrel, BCM bolt, JP carrier, VLTOR upper. Barrel and receiver have M4 ramps, they line up fine. The problem is a failure to feed. The new rounds get caught up on the feed ramp. I've never had a problem with BCM barrels and have quite a few of them. Empty brass kicks out just fine and will lock back on empty mag every time. Gas is not an issue. When the gun is dripping wet it is usually fine for a while. After about 80 rounds it goes tits up. I've tried three different brass cased ammo types. I've swapped complete lowers that have been working for years. I've swapped complete BCG's. I've tried 4 different mags that have been working flawlessly in other guns for 2+ years. Hand cycling rounds is a train wreck. Usually about 50% hang on the feed ramps. |
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Loose magazine catch? Tighten the magazine catch a turn or so.......
Maybe it is allowing the magazine to tilt forward, causing an odd angle for the round to feed from the magazine. Receiver extension have sharp edge or burr? Something sharp catching the brass as it tries to feed? Pictures please......... |
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Prob the end of feed ramps for end burs, and since you did not state which mags you are using, check the bottom of the feed lips for burs as well.
Lastly, since I don't have a JP carrier in front of me to check if it shrouded or not, lets play the devils advocate and call is unshrouded, so check the FP stop collar to confirm that it's not protruding above the carrier ramp/you have a large collar M-16 FP in play, and the hammer is catching the FP collar on the way forward (read produces a jam with the tip of the round just staring to make it way into the barrel extension). |
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