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Question about measuring headspace on Ackley Improved cartridges

Alabama556

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  • May 15, 2008
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    Birmingham, AL
    Can I use the Hornady lock n load headspace gauge for the parent cartridge to measure the headspace on an ackley improved case?

    Thanks so much for the help.
     
    Yes. It's a comparator, not a gauge. As long as you're measuring your fired brass against your resized brass with the same tools you'll be fine.
     
    @Alabama556 I believe a properly chambered Ackley chamber should have .003-,006 crush fit on the parent case. That way you wont run into headspace problems with fireforming.

    I have had a .223,22-250, and 243 win AI. All of them closed with "feel or slight resistance" on new factory parent brass. Cases actually shrink in the fireforming process, so I'm not sure what the headspace gauge for the parent cartridge will do for you, or what you are trying to measure.

    If it's a datum point to determine how much to bump the shoulder w/ full length sizing... it will probably work.

    In addition, besides increased case capacity, the beauty of the PO Ackley design is minimal case growth. Good Luck- I love Ackleys! .
     
    I love them also. I have a 2506ai and 243ai. Perfect for Alabama whitetails.

    I just measured a loaded fire formed case and a fired case from my 25-06ai. The loaded case is .003 smaller than the fired case.
     
    • Like
    Reactions: DIBBS
    @Alabama556 I believe a properly chambered Ackley chamber should have .003-,006 crush fit on the parent case. That way you wont run into headspace problems with fireforming.

    I have had a .223,22-250, and 243 win AI. All of them closed with "feel or slight resistance" on new factory parent brass. Cases actually shrink in the fireforming process, so I'm not sure what the headspace gauge for the parent cartridge will do for you, or what you are trying to measure.

    If it's a datum point to determine how much to bump the shoulder w/ full length sizing... it will probably work.

    In addition, besides increased case capacity, the beauty of the PO Ackley design is minimal case growth. Good Luck- I love Ackleys! .
    The OP is using the wrong terminology, you are correct but you are discussing different tools to what he is referring to
     
    • Like
    Reactions: Yondering
    The OP is using the wrong terminology, you are correct but you are discussing different tools to what he is referring to
    He's not using the wrong terminology - headspace is correct for the difference between chamber and sized brass. It is literally the space between the bolt face and case head. People get too wrapped up in thinking headspace refers only to a go/no-go gauge set, but that's incorrect and is only an estimate of headspace relative to perfectly sized ammo. Actual headspace varies with how much the shoulder is bumped in the sized cases.

    But DIBBS is talking about a crush fit for fireforming a parent case in an Ackley chamber. That's a different thing, where the case and chamber have different shoulder angles.
     
    He certainly is, he is calling a case comparator a headspace gauge which it is not
    OK. It's a comparator, not a gauge. As the second post in the thread already said. But it is a headspace comparator; the OP is fully accurate in using the word headspace.