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Thread: blown primers running 14.5 w/ suppressor

  1. #11
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    Quote Originally Posted by jsebens View Post
    I have personally owned a CMMG gun marked as 5.56NATO that was not. Thanks to them, I spent the better part of a 3-day rifle class shooting a handgun instead...I should probably thank them for all the transition practice. As has been suggested, check the chamber.
    I know the feeling. I have a couple classes coming up and i'm thinking i'll just get a new barrel. It's interesting that i havent had problems till the gun had around 6k through it.

  2. #12
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    Quote Originally Posted by texas12 View Post
    about two weeks ago i did a thoroughly clean and used a parts washer too.


    any time i shoot the gun I clean it and usally thoroughly.


    I have experienced failure to eject a few times, were the spent casing is very tight and i had to hit my stock against the ground to get the round out. I have also experienced failure to eject were the bolt ripped the rim of the casing. I'm starting to think the chamber is the problem.


    The chamber does not seem like its fouled up. Is it possible its time for a new barrel?
    I would seriously recommend considering a new upper. a BCM 14.5" middy w/ appropriate muzzle device would be the bee's knees. I currently own a 14.5" BCM middy that i received two weeks ago...they shoot as soft as everyone says they do.

    When you start adding up the cost of changing barrels, the current sale on complete uppers at BCM makes that seem a little silly, as the prices virtually equal out.

  3. #13
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    Dropped primer. Blown makes me think pierced or blown out around it, what you have is I suspect a normal looking primer that did not stay in the case.

    The increased cyclic rate suppressed shows possible chamber/pressure issues. Or it may just be overgassed without the silencer and then becomes way overgassed with.

  4. #14
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    Quote Originally Posted by Todd.K View Post
    Dropped primer. Blown makes me think pierced or blown out around it, what you have is I suspect a normal looking primer that did not stay in the case.

    The increased cyclic rate suppressed shows possible chamber/pressure issues. Or it may just be overgassed without the silencer and then becomes way overgassed with.
    I have come to the conclusion that it is the chamber and the barrel that is at issue. The primes were in fact blown out. My next step is to get a BCM middy upper have it pinned and just use my existing bolt group and upper. Are their any issues with using my old BCG with the new barrel?
    Last edited by texas12; 10-04-10 at 21:22.

  5. #15
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    I would check the headspace whenever a bolt or barrel is replaced.

    It is very difficult for the primer to be blown out without a KB, generally the bolt face holds in it place while there is pressure in the case. If the case head is expanded from excess pressure or has not had time to retract (extracting faster because of the higher cyclic rate with silencer) the primer may drop out when the case is ejected.

    You probably have a pressure/chamber issue.

  6. #16
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    Quote Originally Posted by Todd.K View Post
    I would check the headspace whenever a bolt or barrel is replaced.

    It is very difficult for the primer to be blown out without a KB, generally the bolt face holds in it place while there is pressure in the case. If the case head is expanded from excess pressure or has not had time to retract (extracting faster because of the higher cyclic rate with silencer) the primer may drop out when the case is ejected.

    You probably have a pressure/chamber issue.
    Thanks for the help, I'm going to order a complete upper w/ bolt and call it a day.

  7. #17
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    Not sure how many rounds are through the barrel or how long you have had it. But, I would at least contact CMMG and let them know the issues you have or had. Especially since their website claims that they are milspec barrels.

    I believe that one of their reps even posted here on M4C. I would look for that post.

    I find it especially interesting that their website states any use of steel case ammunition will void their warranty. Why is that? My AR's are all able to shoot Hornady steel case 55gr. TAP without problems.
    Last edited by Iraqgunz; 10-04-10 at 18:46.



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