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MX-8 misfiring

Discussion in 'Shooting Related Threads' started by michmoe, Sep 12, 2013.

  1. michmoe

    michmoe TS Member

    Joined:
    Jan 29, 1998
    Messages:
    726
    My MX-8 is misfiring on the top barrel and I can't figure out why. I just had Dan at Giacomo's go through the gun, replace firing pins, springs and the like and I am still having problems. My question is I shoot a very light 1 0z. load for the first shot in doubles. Is it possible that my first shot is so light that its not fully cocking the top barrel when the bottom barrel fires? The gun's bottom barrel is over bored at .740 and ported as well. The primers are hit, but not hard enough to fire and I've tried it with new shells with no different effect. HELP!!!
     
  2. Ajax

    Ajax Well-Known Member

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    Jan 29, 1998
    Messages:
    2,446
    If the primer is hit on the top barrel, it's cocking the top hammer. I would make sure the cocking foot is not sticking/rubbing against the hammer.

    Ajax
     
  3. Don Rackley

    Don Rackley Well-Known Member Supporting Vendor

    Joined:
    Jan 14, 2007
    Messages:
    1,239
    Michmoe,

    A Perazzi cocks both hammers when you open the gun, so that is most likely not the problem.

    I would check the following items:
    1. Replace the top barrel (left side) hammer spring and see if that corrects the problem
    2. Take the stock off and see if there is evidence of the top hammer rubbing the wood inside the stock. If there is, remove some wood with sandpaper.
    3. Take the trigger out and try to find any binding of the following parts; left hammer, left cocking foot and left side ejector trip rod in the receiver.

    Good luck, let us know how it works out.

    Don
     
  4. michmoe

    michmoe TS Member

    Joined:
    Jan 29, 1998
    Messages:
    726
    Thanks guys, I'll look into it and keep you posted. David, you might have something there. My forend is hard to get to latch and might be suspect. How long did Lucio have to have your gun? Maybe I'll just send it to him.
     
  5. Barry C. Roach

    Barry C. Roach Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    9,209
    Location:
    Scottsdale, AZ
    What David said. The cocking bar that travels through the "dove tail shaped" cutout in the bottom of the receiver is sticky. When the gun cocks that bar is supposed to go back to it's "home position". When it get gummed up it wont. Consequently, when the hammer drops there's a "domino" effect that is forced to drive the cocking bar back to it's home position. That effect uses up a bunch of energy used to drive the firing pin and you get a light hit.

    I'd clean and relube that dove tail groove, the cocking bar, take out both cocking shoes in the trigger cleaning and relubing them too. Also remove, clean and relube both hammers. If you want be real thorough make sure the spring "stirrups" are cleaned and relubed too.

    Many, many P gun shooters neglect cleaning the cocking bar and groove. Many a firing pin and hammer spring have been replaced when the culprit is a sticky cocking bar. Good luck.
     
  6. michmoe

    michmoe TS Member

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    Jan 29, 1998
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    Thanks Barry, What do you recommend lubing with? I can use either trigger (one a Precision the other an Allems and they both work fine in my GA1 O/U.
     
  7. GunDr

    GunDr Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    2,913
    just to follow up on the cocking bar issue, you can remove the buttstock and using your finger push the hammer forward against the firing pin, the hammer should make contact with the back of the receiver. the gun does have the rebounding hammer so when you release the hammer it should rebound back and be free of the firing pin or at least allow the firing pin to be fully retracted into the face of the receiver.

    if the hammer does not make on with the receiver, cocking bar can be too long or the cocking piece in front of the hammer can be too large
     
  8. Barry C. Roach

    Barry C. Roach Well-Known Member

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    Messages:
    9,209
    Location:
    Scottsdale, AZ
    I use Triflow for the cocking bar and the dovetail groove. Some under the hammer stirrup where the springs hook makes contact, the cocking shoe pins, the hammer pins and the little plunger and return spring that fits down the forked end of cocking bar.

    SuperLube grease on the contact areas of the cocking shoes and the cocking bar where they meet and the interface between the hammers and the cocking shoes. Hope that takes care of your misfires.

    Listen to the advice of the GunDr too.
     
  9. JT 27

    JT 27 Member

    Joined:
    Dec 13, 2012
    Messages:
    616
    Had problems twice, 1st time was a bent cocking rod, 2nd time was a PFS stock not allowing enough recoil, fixed with a ..410 inertia block.
     
  10. michmoe

    michmoe TS Member

    Joined:
    Jan 29, 1998
    Messages:
    726
    Problem seems to be solved and thanks to all responders. I took the stock off and cleaned and lubed the cocking rod. I then took a rattail file to the groove in the stock where the cocking rod sits. Put the gun back together and after firing at twenty-five pair, never had a misfire. I didn't do anything with the triggers as they both worked fine in my other P-gun with no misfires there. Thanks again...Hugo Rinke