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Thread: useful info on pressure signs

  1. #1

    useful info on pressure signs

    happy new year!!

    not sure if anyone has posted this link but being new to reloading i have been looking for information about pressure signs and tripped over this site. very informative for me, so thought i would pop it up in case anyone else is interested.

    cheers

    MassReloading -

  2. #2
    Looking at primers is NOT the way to judge pressures ............................................... measurements at the pressure ring on the case is a far better way.

  3. #3
    no i know that now from reading other things, sorry i maybe should have qualified my post with a note to say they are a bit unreliable, it was more for the pictures of extractor marks etc thati was interested in. maybe it can be useful for someone. incidentally is this pressure ring just above the extractor groove, and i take it you compare a reading to a new case? or does it need to be a case which has been fired with a known safe load?

    sorry for all the questions but i havnt been able to find much info on this method.

    thanks.

  4. #4
    Quote Originally Posted by hcm1 View Post
    no i know that now from reading other things, sorry i maybe should have qualified my post with a note to say they are a bit unreliable, it was more for the pictures of extractor marks etc thati was interested in. maybe it can be useful for someone. incidentally is this pressure ring just above the extractor groove, and i take it you compare a reading to a new case? or does it need to be a case which has been fired with a known safe load?

    sorry for all the questions but i havnt been able to find much info on this method.

    thanks.
    'pressure ring' oh well...

    Case Head Expansion is measured above the extractor groove and the comparison is made before and after firing - not against another piece of brass.

  5. #5
    For the hand loader using the pressure ring measurement one usually fires a few factory rounds and measures the pressure ring and makes a note of this and then compares the hand loads to this.



    The pressure rings forms where the case wall joins the base inside the case.

    The three cases are L-R 30-30 Winchester, 6.5x55 Norma and 270 Winchester. Of interest to me at least is the fact that the highest pressure round has the thinnest wall from body to primer pocket.

  6. #6
    The proper method of the pressure method is to get an average of measurement of 10 cases from factory loads, then compare it your handloads. Use the same make of brass for your comparative tests.~Muir

  7. #7
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    Looking at primers is NOT the way to judge pressures ............................................... measurements at the pressure ring on the case is a far better way.
    Correct as far as we are concerned here, for rifle cartridges.

    And then, as also noted, to compare it against the pressure ring for factory ammunition fired in the same rifle.

    Primers can and do vary between makers and what primer Federal use in that particular batch of factory ammunition may not be the same primer that comes sold loose in a sleeve with the Federal name on it!

    However it has and remains a very useful guide for pistol calibre cartridges fired in pistols or revolvers.

  8. #8
    Quote Originally Posted by enfieldspares View Post
    Correct as far as we are concerned here, for rifle cartridges.

    And then, as also noted, to compare it against the pressure ring for factory ammunition fired in the same rifle.

    Primers can and do vary between makers and what primer Federal use in that particular batch of factory ammunition may not be the same primer that comes sold loose in a sleeve with the Federal name on it!

    However it has and remains a very useful guide for pistol calibre cartridges fired in pistols or revolvers.
    "However it has and remains a very useful guide for pistol calibre cartridges fired in pistols or revolvers! which is about useless in the UK of course.

    I also recall that it will depend on the breech face to cylinder gap on revolvers. I also recall that some S&W's were quite sloppy in this respect. I had a model 19 that was awful and how it ever passed inspection let along proof I still wonder at. It was returned for a full refund.

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