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What is safe headspace?

Discussion in 'Uncategorized Threads' started by perga1, Jun 27, 2008.

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  1. perga1

    perga1 Active Member

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    What is considered safe headspace for a shotgun? I never had a shotgun before that I could see between the monoblock and receiver face until the one I just bought. It shoots fine but I know it isn't right because none of my other shotguns have visible headspace. JRM
     
  2. shot410ga

    shot410ga Well-Known Member

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    Headspace is determined by go-nogo headspace gauges. Unless you have a set, you'll never know if you have a problem or not.
     
  3. GunDr

    GunDr Well-Known Member

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    Even if the breech faces are tight to one another (no gap), you still can have excessive headspace if the chamber was cut too deep.

    Having guages may not always be neccessary if you know a few certain dimensions and have access to a depth micrometer.

    The "GO" guage....The gun will close and lock up. It's rare that the "GO gauge" get's used often. About the only time it's used is during chamber work...ie-manufacturing or sleeving a chamber. If the chamber is properly done, the "GO" gauge will be flush with the bbl's breech face.

    The "NO-GO" gauge.... Comparing the two Clymer gauges I have, the difference is about .011". This measurement comes only in the thickness of the rim, with the NO-GO being thicker.

    So what can be determined without the gauges??. Using the .011" difference, by dropping in a new shell (BE SURE TO REMOVE THE BBL FROM THE GUN!!!!!), and using a depth micrometer, if the depth from the bbl's breech face is less than .011", but not sticking above the face, you're good to go. If the shell is sitting deeper, have a gunsmith check it out.

    There are quite a few guns being shot today that are beyond the .011", and show no signs of excessive headspace, for example..primers backing out or rims splitting.

    Doug Braker
    Doug
     
  4. perga1

    perga1 Active Member

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    Thanks Doug that was very useful info. Out to the gartage now to dig out the depth Mic. There is no primer popping or rim splitting. Jim
     
  5. JLW

    JLW TS Member

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    I have read if you can close the bb'l on a .010" shim you should have the gun looked at.-Jerald
     
  6. GunDr

    GunDr Well-Known Member

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    I should maybe clarify the .011" I mentioned earlier. The above is assuming that there is NO gap in the breech face.

    When you add in a gap, measured with different shim stock, this has to be included in the .011"

    For an example...A measurement from the bbl's breech to the shell is .008" (this is OK), add in a breech face gap of .005", you now will have a gun with excessive headspace, .013".

    Having a gun with the .013" measurement, wouldn't bother me, it's only .002" out of spec. I'd be more concerned with the .005" gap.

    Doug
     
  7. phirel

    phirel TS Member

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    Doug- You will probably not like my quickie test, but if I can't close the gun with a thin sheet of paper on the breech face, the gun passes my first head space test. If the gun will close without tearing the paper, I conclude there could be a problem. Next, I put in a new shell and rub my finger over the head of the hull and the edge of the barrel. If I don't feel a ridge, I don't worry. I do not have a set of 12 ga go/no go gages, but I do have a lot of paper and several fingers.

    Pat Ireland
     
  8. perga1

    perga1 Active Member

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    Thanks for the contributions to the thread. I will rest easier now, but it is still a little unnerving to be able to see light through the action when closed. I have never owned a shotgun before where that was possible. Thanks again, Jim
     
  9. GunDr

    GunDr Well-Known Member

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    Pat,

    I don't see a problem with that. A piece of paper is about .003"-.004" in thickeness.

    Doug
     
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