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Posted: 10/22/2008 7:47:22 AM EDT
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OK so here's the deal. Reference BCG = Colt Std M16 BCG MPC etc... Problem BCG = DPMS Chromed Slickside both new. Starting with a clean rifle and well lubed BCG the DPMS BCG functons fine for 30-90 rounds. At some point in there and it has not been consistent it will suffer two issues. With normal lube it will begin to misfeed after each shot, ejection is fine, however feed will lock with the next round on a 45 degree slope into the extension. With heavy lube this problem will be intermittement happening much less frequently (still 30+ rounds from clean to get it going) however the second problem will show up which is failure 90%+ to lock open on empty. NOW... Take the Colt bolt from the reference set and place it in the DPMS carrier... Function restored to normal for 200+ rounds (on three occassions) Take the DPMS bolt and place it in the Colt carrier, all of the above problems transfer to the Colt carrier. NET... It has to be something with the bolt vs. carrier... but what? Actions taken that have not resolved: 1. Gas rings changed 2. Bolt polished with 800 grit paper Your thoughts are appreciated. |
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Could you provide the following information: 1. What kind of upper/lower are you running? 2. Does your upper have M4 ramps or Rifle ramps? 3. Are you running M16 or AR15 carriers? I'm inclined to agree with you about the bolt simply due to the fact that the problems transfer when you swap them out, but I don't like ruling anything out initially. A couple bushmaster uppers that my father in law bought were junk from the factory, with the EXACT symptons that you're describing. After about 10 rounds they turned into bolt actions. The round would hang up on the feed ramp, and would only feed once you pulled the charging handle back to the rear and let it slam the round home into the chamber. Bushmaster's solution? They took the rifle ramped uppers that my FIL returned, cut M4 ramps into them (or just replaced the whole upper, not sure), and replaced the bolt. Problem solved. More than likely your bolt is out of spec. Get a new bolt or return it to where you got it and get your money back...although now that you've taken sandpaper to it you might be out of luck on a return. |
I'm aware of that, but stranger things have happened. Just sharing my experience. If you're sure it's the bolt that's out of spec, then replace it. There you go, problem solved. |
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