dominator probe seal

Discussion in 'Walther' started by hmangphilly, Dec 12, 2013.

  1. hmangphilly

    hmangphilly The Doctor

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    evening all

    i'm getting a little poof,.... if I dust talcum powder around the breech and fire a pellet.
    obviously the seal is having a little leak.
    has any one got one or just tell me the size please. I haven't removed the old one yet ,it looks like a bit of a work up .

    and

    the pellet probe is slightely mis aligned to the left .
    its not scraping the action but right at the end of the closing stroke , you can see the taper just push it over towards the centre of the barrel.

    can any thing be done here to straighten it all up and avoid the wear that will result if left wonky
     
  2. villiers

    villiers Self appointed antipimp

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    O ring

    4mm x 1mm the o ring what is it like when you close the cocking lever the last bit does it feel like its going over center and pushing the seal hard up into the barrel taper? barrel depth may have to be reset .
     
  3. hmangphilly

    hmangphilly The Doctor

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    that's it don it feels a bit snug right at the end .
    it looks like its centralising itself too....could be my wonky eyes ...i'll look closer
    how to do the barrel depth ?
     
  4. RobF

    RobF Administrator Staff Member

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    Got one here... ;)

    The seal change sorted out my probe which also went left... Bit up to my neck in it but i can talk you though it :)
     
  5. hmangphilly

    hmangphilly The Doctor

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    hey up rob
    just went and got some 4x1
    and a couple 9 x 1.5 for the barrel

    having a go now.
    whats that you can talk thru mate , the barrel setting?

    ive just got the probe out and doing the seal
     
  6. RobF

    RobF Administrator Staff Member

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    Oh no worries... i've not moved my barrel. Try it without doing it and see if it's ok.

    A trick is to hook some wire in the rear loop of the spring... then put the cocking assembly back on, then pull the spring rear loop out and attach the button, dispense with wire.
     
  7. hmangphilly

    hmangphilly The Doctor

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    ok done that.
    new seal fitted , probe back in
    now then
    this barrel depth....
     
  8. RobF

    RobF Administrator Staff Member

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    Never done it... as far as I know, three allen bolts top of breech, central one is V shaped to locate the barrel precisely. But i'm not sure yours has ever been off.

    Look at it when Don does your shroud. But for me changing the o-ring sorted the left issue. It seems to get a bit of lateral force from the cocking mechanism.
     
  9. hmangphilly

    hmangphilly The Doctor

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    seems to be ...
    the centre screw of the 3 has a pointed tip and locates into a pointy countersunk hole.
    the other 2 have flat tips and tighten against corresponding flat surfaces machined in the barrel.

    I haven't done any thing particularly scientific.
    roughly lined up the barrel by looking down the screw holes
    just finger tightened the outer screws then backed off 1/4 turn.
    tightened the centre screw in small increments till it engaged the barrel .
    kept tightening centre screw in small increments and alternately closing the cocking lever till I could feel resistance as the probe and seal seated and the lever went over centre to the full closed position .tightened the outer 2 screws.

    covered the breech area with talc and fire a shot to check for leak.

    and just kept repeating until no puff of talc.
    final tighten up of outers to hold the barrel firm....not too tight ... then just nipped the centre back up ljust so it seats, the outers are doing the work.
    recheck the cocking lever to ensure it's not over stressed
    seems ok
    and no leaks
    the puffs I did get through the process seemed to come from barrel to action rather than probe but after gradual adjustment this has now stopped .
    it has to be said that the centre screw is just about bottomed now but any less gave barrel to block leak.
    if there's a better way
    please let me know
     
  10. hmangphilly

    hmangphilly The Doctor

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    well somethings happened .....15 more fps on the chrony
    ....i'll shoot some strings tomorrow ....long day today.
    thanks fellas
     
  11. Numb Nut

    Numb Nut New Member

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    I would say that the barrel to block area shouldn't leak due to the 2 o-rings around the barrel, one either side of the transfer port - or am I thinking of a different rifle?
     
  12. hmangphilly

    hmangphilly The Doctor

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    you are right
    the only way I can explain it is that the end o ring needs compressing between the block and a shoulder on the end of the barrel.
    tightening the tapered screw pulled the barrel toward the block and gave the o ring a squeeze
     
  13. Numb Nut

    Numb Nut New Member

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    To remind myself of the how the o-rings are arranged on the barrel I searched the forum and found this:
    http://www.shooting-the-breeze.com/forums/showthread.php?t=4740

    That's not actually a walther factory barrel but I think the relevant details are correct.

    So the rear o-ring doesn't sit in a groove but just takes up the space between the barrel shoulder and the ledge inside the block. I guess you could replace that o-ring to ensure it's a snug fit so you don't have too much tension on the cocking lever and on the pin that pushes the bolt forward.
     

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