Gas tube leaking at front sight

Discussion in 'AR-15 Discussion' started by Rhino24, Nov 14, 2012.

  1. Rhino24

    Rhino24 New Member

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    I have a 16 inch barrel upper that has gas tube is leaking carbon at the front site and cause sometimes some failure to feed. What can be done?
     

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    Last edited: Nov 15, 2012
  2. JonM

    JonM Moderator

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    is the gas block leaking where it connects to the barrel?? or is it leaking around the tube?? hard to tell without pics. might be as simple as a new roll pin or mis sized tube worn tube or wrong sized block or loose gas block.

    good close up pics might help
     

  3. Rhino24

    Rhino24 New Member

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    Ok I don't see much from the last Range Trip. This time It would have a few failure to cycle the hammer back. Then ran fine but would not lock the bolt back on empty mag.
     

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  4. JonM

    JonM Moderator

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    Are you running suppressed?? that happens a lot with suppressors in regards to blowby.

    If you have a bad lever that is a huge cause of fail to lock back

    Gas tube prolly is partially plugged may need a cleaning or replacement
     
  5. Jpyle

    Jpyle New Member

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    Gas leak will cause all the problems cited. As JonM stated might be simple as repositioning the gas block or changing the tube but impossible to diagnose remotely. Anything appear loose, is sight post canted to left or right, is carbon on barrel or on gas block near pin or tube opening?
     
  6. Rhino24

    Rhino24 New Member

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    This is a new upper with a 16 inch barrel , the fowling residue that I found was on the stainless steel tube. No suppression just A2 bird cage. I will take off the Magpul BAD lever next time I fire it.
     
  7. ZeusEcho

    ZeusEcho Member Lifetime Supporter

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    Is it because of the lever itself (weight or interference with part of the lower) or from the shooters trigger finger hitting it?
     
  8. JonM

    JonM Moderator

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    Per bravo company tech rep is it adds just enough mass and resistance on some guns to the bolt catch to delay it rising fast enough to catch the bolt

    The bad lever isnt the cause of the gas blowby but its prolly the cause of the fail to lock open
     
  9. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The cheap method is to simply replace the gas tube. If you still get the blow by, the gas block (FSB) needs to be replaced. If it is new, I would contact the manufacturer.
     
  10. Rhino24

    Rhino24 New Member

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    Do you think it could start to seal it self up? The more powder down the pipe. The reason I ask is that now it's just doing it on the first mag then runs fine.
     
  11. NickySantoro

    NickySantoro New Member

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    OP,
    A lot of ARs will leak a little bit at first but seal themselves up. Usually it's not leaking as bad as it seems. The question that was not asked is what ammo are you using? Sometimes weaker than spec ammo will cause the type of malfunctions you describe in a new, tight, or possibly under-lubricated gun.
     
  12. fsted2a

    fsted2a Active Member

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    I am thinking your gas block is not to spec. This is the first I have seen or heard of this problem. Like Robo said earlier, since it is a new upper, take it back where you bought it and have them fix it. You shouldn't have this problem, no matter what ammo you run through it.
     
    Last edited: Nov 20, 2012