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Thread: Intermittent extraction problem

  1. #11
    Join Date
    Jun 2013
    Posts
    473
    Feedback Score
    16 (100%)
    Alright, I replaced the extractor spring/insert and lubed up the BCG without cleaning anything and put everything back together. I'll see if the malfunction comes back in a couple hundred rounds. If not, I'll put back the old spring and the FTEs should come back.

    The left spring is a brand new one before installation. The middle one is the suspect spring that's taken a set after installation and under 300 rounds fired. The right one is the stock spring/o-ring (no insert) that came in the C4 BCG.



    Here's what the chamber looks like. There was a loose piece of brass shaving that I was able to blow out with my mouth. I don't think that had anything to do with the FTEs because the last rounds fired in my shooting session didn't malfunction.


  2. #12
    Join Date
    Jun 2013
    Posts
    473
    Feedback Score
    16 (100%)
    Shot 120 rounds after replacing old BCM extractor spring with new BCM extractor spring and didn’t have the failures. I’ll keep a round count and move on.

  3. #13
    Join Date
    Sep 2015
    Posts
    176
    Feedback Score
    1 (100%)
    Your bolt face might be too big or the extractor recess cut in bolt isn't deep enough or the extractor hinge pin hole is drilled too far out of bolt body an extractor no matter how good or not the extractor might be, it might not be able to get in position for the claw fully envelop the rim. Try this, with BCG removed from rifle use good fired case, roll case in bolt mouth by having rim under extractor then roll case in to be inline with bolt compressing the ejector spring then when case is fully in bolt face push and wriggle case directly away from extractor and look how much of claw is enveloping the rim should lose hardly any engagement when you push case away from extractor inside bolt face. When the case is in bolt face it shouldn't have hardly any slop for it to move away from the extractor and the extractor should be fully enveloped on rim to point the recess on extractor itself for the very outer edge of the rim is what stopping extractor from going further onto the rim. The angle of inside the claw should be flat with the rim or on aggressive side where it the very edge of tip width of the claw is touching inner of rim and as you go into back inner claw it depart pressure or contact from rim slightly. It should not be opposite of aggressive engagement where it's sloped on rim that tip isnt touching the inner rim and as you go along to backside into the inner back of claw it starts to contact outer edge area of case rim. Will make illustration if requested.

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