Strange .22 firing problem...

Discussion in 'Gunsmithing Forum' started by jwfilion, Apr 24, 2013.

  1. jwfilion

    jwfilion New Member

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    I was asked to take a look at a friends Cooey 600 that he inherited. He encountered some misfiring when he tried it out. Thought it was really old ammo, as only one of every 5 or 6 fired. I had a spare bolt, so I fitted it nicely to the gun. Still misfires. The chamber face looks as good as the model 60 I have, and mine shoots well. There are no burrs getting in the way of the firing pin. I tested the bolt face with machinists bluing and the bolt face is making contact with the chamber face. Can't get my head around it.
    Then...while testing it this morning, I discovered that if I put forward pressure with my thumb on the bolt handle base and pull the trigger, every shell will fire! No pressure, no firing! If the fit is that close, how can a little pressure on the bolt make that much of a difference? Can anyone give me an idea as to what is going on?
     
  2. Hawg

    Hawg Active Member

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    Worn firing pin or weak spring.
     

  3. danf_fl

    danf_fl Retired Supporter

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    It sounds like the spacing is off.
    The rim needs to be tight against the barrel for the firing pin to have the most smacking power.

    "... how can a little pressure on the bolt make that much of a difference?"
    Easy, you are applying pressure so the round has no forward movement anymore when hit by the firing pin.
    Without the forward pressure, the firing pin moves the round forward instead of hitting the rim against a firm surface.

    Does that make sense? It is a little difficult to describe.

    Is there any way for the bolt handle to get a shim behind it in the "in battery" position?
     
    Last edited: Apr 24, 2013
  4. jwfilion

    jwfilion New Member

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    Thanks for the reply. I doubt that the pin or spring is the problem, as the bolt was new, however I've made that mistake before. I will take it apart to examine the insides.
    As for the spacing, it does make sense. I did use a go gauge to fit the bolt, maybe should have used a dummy round. The fact is, when the head of the bolt contacts the face of the chamber, the bolt just closes. I wanted no play at all. So I guess there is no room for a shim, unless I make room. How would I go about this? If the face of the bolt contacts the chamber face, perhaps the judicious removal of some material from one or both surfaces would not only increase contact with the shell, but also make room for a shim on the bolt handle. I'm always open to suggestions. There are a gazillion of these Cooey repeaters up here and I'm bound to meet more of them.
     
  5. danf_fl

    danf_fl Retired Supporter

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    If you can put forward pressure on the bolt handle and it works, then look at some way to keep the bolt handle pushed forward.

    If the area of the bolt handle is worn, you may have to concentrate there and add material.
     
  6. jwfilion

    jwfilion New Member

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    Hmmm...I noticed something else. There seems to be a little powder residue on the upper face of the bolt, radiating outward from around the firing pin. Never noticed before. I wonder if this means the chamber face, that is in contact with the shell rim, has been eaten away over the years to a point that the firing pin is just out of reach of solid contact with the rim. I don't think it is "shot out" as the go and no-go gauges seem fairly snug in the bore.
    I also discovered that the firing pin in these Cooey 60/600s is held in by a pin. It does not pass through the bolt, so it can not be driven out, it must be drilled out...gently!
     
  7. danf_fl

    danf_fl Retired Supporter

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    Good luck to you!
     
  8. orangello

    orangello New Member

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    Honestly, this thread reads like the narration of a porno. No pics?
     
  9. jwfilion

    jwfilion New Member

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