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Thread: Critical Failure - Seeking Advice

  1. #31
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    I would not bitch at RCA if I were you(the OP), frankly, I am amazed that extractor wasn't bent back like a over-cooked noodle.
    Last edited by Heavy Metal; 07-06-13 at 23:07.
    My brother saw Deliverance and bought a Bow. I saw Deliverance and bought an AR-15.

  2. #32
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    Quote Originally Posted by Heavy Metal View Post
    I would not bitch at RCA if I were you(the OP), frankly, I am amazed that extractor wasn't bent back like a over-cooked noodle.
    Let's see...

    Bcg held up damn well.
    Rca doesn't think their product caused the issue at all
    Rca is replacing their now damaged product at no cost...just cause.

    Wtf could anyone have to say about them that's negative?

  3. #33
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    Out of battery fire due to primer not being fully seated in pocket, Is my best guess. If not mistaken (probable am), excessive headspace failure looks like incipient case head separation(usually related). The excess space from the datum line on shoulder to bolt face, allows excessive metal stress. But happens in "ring" pattern and is noticeable on brass above web. https://www.google.com/search?q=inci...w=1347&bih=604
    ^^ Read with southern accent !^^ and blame all grammatical errors on Alabama's public school system.
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  4. #34
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    Assuming nothing else was wrong, no bad parts, etc. the firing pin won't protrude fully until the carrier is fully seated. This means the gun won't fire until the carrier is fully seated. I've heard of a few theories that explain how an out of battery firing can occur in an AR but its still a rare thing to happen.

    OP, did you pull the trigger on the bad round or did it just go off on its own as it was chambered?

    Eta: If you don't have the tools to measure your previously fired cases I can measure them if you want to send me a few.
    Last edited by Eric D.; 07-07-13 at 00:48.
    B.A.S. Mechanical Engineering Technology

  5. #35
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    I'm with IG on this one. If the bolt lugs are indexed with the RE lugs then the weapon is in battery. I cannot see how this is an excessive headspace issue when the weapon had fired dozens of rounds previous to the failure. If the headspace were that far out then it would have shown up as split or separated case heads. It looks as if the case was weak and the pressure found the path of least resistance. Damn scary considering the OP was a lefty.

  6. #36
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    Quote Originally Posted by Iraqgunz View Post
    The ammo is the problem here. Just a few days ago my SBR blew up. The barrel was a BCM 12.5" w/an LMT enhanced carrier and BCM bolt. Upper had about 8K through it and had functioned 100% without issue.

    The ammo was some remanufactured stuff that was supposed to be good to go. Unfortunately it wasn't. The carrier split at the bottom, extractor was trashed and the upper was bulged. I haven't been able to inspect the barrel yet.

    My round looked almost identical to yours.
    I'd place my bets on this.

    Here is some overpressured 7.62x51 that let go. the one on the left looks similar to the OP's case.


  7. #37
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    Quote Originally Posted by Iraqgunz View Post
    The ammo is the problem here. Just a few days ago my SBR blew up. The barrel was a BCM 12.5" w/an LMT enhanced carrier and BCM bolt. Upper had about 8K through it and had functioned 100% without issue.

    The ammo was some remanufactured stuff that was supposed to be good to go. Unfortunately it wasn't. The carrier split at the bottom, extractor was trashed and the upper was bulged. I haven't been able to inspect the barrel yet.

    My round looked almost identical to yours.
    Yikes!

    Glad everybody's OK.

    What causes the carrier to split?

    That seems common with KBs.


    OP,

    Is the barrel a true 5.56 chamber?

    Possible high pressure loads in questionable chamber causes overpressure and case failure...
    Last edited by Clint; 07-07-13 at 14:58.
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  8. #38
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    I've always thought it was due to excessive pressure building in the carrier as it attempts to cycle.

    Quote Originally Posted by Clint View Post
    What causes the carrier to split?
    B.A.S. Mechanical Engineering Technology

  9. #39
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    One thing to remember!!

    Always, and I mean always wear your safety eyewear. This could have had disastrous consequences. Carry on.

  10. #40
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    UPDATE

    To update on this issue-

    I received a brand new BCG from Rubber City Armory last week. I used Clymer 5.56mm GO and NO-GO headspace gages, and the bolt closed in the barrel on the GO gage, and failed to close on the NO-GO gage. Good news. Rubber City Armory reported to me that they replaced the bent extractor on my original BCG and have been shooting it for evaluation with no issues. They were pleased that the assembly withstood the overpressure round with only the bent extractor.

    I am using a Wilson case gage on my remaining PPU ammo, and after 200 rounds, have yet to find anything that fails at this point.

    I swapped the Extra Power buffer spring with one of the regular buffer springs that I got from a backorder.

    I have deep cleaned and inspected the entire upper and barrel, and have not found anything that would speak of any further damage or defect.

    I hope to get it out and shoot it soon, but at this point I am very positive with the outlook that the issue was ammo related and aside from the bent extractor no damage was done to the rifle.

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