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  1. #1
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    Bolt won't lock back

    So I decided to go shooting today. Noticed that my bolt won't lock back on the last shots which pissed me off because I spend good money.
    I tried different magazines (gen 2 and 3 pmags). Ammo was federal 55gr 5.56 fmj.
    Was thinking either it's the ammo, the buffer spring is to strong, buffer to heavy or something wrong with the bolt catch.

    It catches when I put an empty mag and rack it manually.


    Specs:
    Spikes tactical gen 2 billet lower
    Damage industries enhanced carbine buffer spring
    Spikes tactical t2 buffer

    Upper:
    Long dog tactical bcg
    Daniel defense 14.5" mid length pinned spikes tactical barking spider 2 pin/weld


    What do you guys think?


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  2. #2
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    Try a standard carbine buffer and spring. That would be my first attempt to fix the problem.

    Never heard of the BCG but I assume a standard phosphate milspec BCG?

    What gas block are you running?

  3. #3
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    Quote Originally Posted by Dstrbdmedic167 View Post
    Try a standard carbine buffer and spring. That would be my first attempt to fix the problem.

    Never heard of the BCG but I assume a standard phosphate milspec BCG?

    What gas block are you running?
    Daniel defense from factory, pinned. BCG I won it from stickman last Halloween. :) it's nickel boron.

    Oh and oil used is frog lube. Which I hope isn't making the bolt catch stick.


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  4. #4
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    Quote Originally Posted by nCarnage View Post
    Daniel defense from factory, pinned. BCG I won it from stickman last Halloween. :) it's nickel boron.

    Oh and oil used is frog lube. Which I hope isn't making the bolt catch stick.


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    Missed that my bad... Good win! I don't think froglube is you're issue. In fact the video's just posted are using a new ucwrg BCG that I slapped some froglube on before I hit the range.

  5. #5
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    All righty. I shall try swapping the buffer on my next outing with the other rifle. See if that's the problem before I start ordering parts


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  6. #6
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    Also try different ammo before you change anything and then use the federal with a spring change if the problem persists..

  7. #7
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    Also recall swapping uppers and it did the same thing


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  8. #8
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    BCG is where I'd start.

  9. #9
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    Did u cheak your bolt catch to see if it to tight
    $300 and 10 Pastrami Sandwiches and a case of Diet Coke. ( UWone77)

  10. #10
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    Bolt won't lock back

    Quote Originally Posted by toolboxluis00200 View Post
    Did u cheak your bolt catch to see if it to tight
    Would release easily on both ambi controls. Bcg was thinking about buying one anyway. Think I have a spare buffer spring somewhere.
    Appreciate all the input


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  11. #11
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    Hope u get it fix
    $300 and 10 Pastrami Sandwiches and a case of Diet Coke. ( UWone77)

  12. #12
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    Quote Originally Posted by toolboxluis00200 View Post
    Hope u get it fix
    Yeah. I hope so too. Need to fix it before May 2016 which is plenty of time. Just my gun fund will become a no-Gun fund.


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  13. #13
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    Quote Originally Posted by nCarnage View Post
    Yeah. I hope so too. Need to fix it before May 2016 which is plenty of time. Just my gun fund will become a no-Gun fund.


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    You must have a little one on the way... If so congrats!

  14. #14
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    Quote Originally Posted by nCarnage View Post
    Also recall swapping uppers and it did the same thing
    Double check this.....if the bolt won't lock back with either upper, it's in your lower. If you have another bullt up lower, you can verify that your new upper functions on that old lower as verification.

    And you said the bolt will catch if you rack with an empty mag and release properly with all controls, so I don't suspect a problem with the catch. I would check the buffer and edges/inside of the extension to see if there is obvious evidence of friction (just barely short stroking) and check for magazine wobble in the well that might prevent latching under firing conditions. I've had enough strange malfunctions with billet lowers that I wouldn't be terribly surprised if it were a mag fit/tolerance issue. Failing to find a problem with that, I would swap the spring first, then the buffer (using the older upper that you know works first) to see if you can isolate a problem point.

    Ulitimately, all this troubleshooting is done most easily if you can isolate increasingly smaller groupings of components as the issue. Good luck.

  15. #15
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    Quote Originally Posted by RiverRat View Post
    Double check this.....if the bolt won't lock back with either upper, it's in your lower. If you have another bullt up lower, you can verify that your new upper functions on that old lower as verification.

    And you said the bolt will catch if you rack with an empty mag and release properly with all controls, so I don't suspect a problem with the catch. I would check the buffer and edges/inside of the extension to see if there is obvious evidence of friction (just barely short stroking) and check for magazine wobble in the well that might prevent latching under firing conditions. I've had enough strange malfunctions with billet lowers that I wouldn't be terribly surprised if it were a mag fit/tolerance issue. Failing to find a problem with that, I would swap the spring first, then the buffer (using the older upper that you know works first) to see if you can isolate a problem point.

    Ulitimately, all this troubleshooting is done most easily if you can isolate increasingly smaller groupings of components as the issue. Good luck.
    Thanks. Will do that.


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