? on Lyman Case Length Headspace Gauge

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  • Doco Overboard

    Ultimate Member
    Was the case resized in a different batch or did you install/remove your dies and work on other cases? if you didn't have to do that, slow down and make sure the press ram is raised lowered consistently for each and every case.
    I know its hard to do when your looking at a pile of brass trying to make it smaller. Could be just that its not resized all the way.

    I forgot to add different head stamps may have slightly different rim thickness plus some tolerance differences in machining between brand names of the case gauges. The fit of the case in your gun is the best gauge. See if a 5% one will chamber with no resistance on a stripped bolt.
     

    Seagrave1963

    Still learnin'
    MDS Supporter
    Feb 6, 2011
    10,003
    Eastern Shore
    Was the case resized in a different batch or did you install/remove your dies and work on other cases? if you didn't have to do that, slow down and make sure the press ram is raised lowered consistently for each and every case.
    I know its hard to do when your looking at a pile of brass trying to make it smaller. Could be just that its not resized all the way.

    Same batch and didn't change out dies - all 50 sized in one sitting. I run each case twice in the die spinning it halfway between each "ram". No visible damage on any of the cases that don't seat in the Lyman gauge either.
     

    Seagrave1963

    Still learnin'
    MDS Supporter
    Feb 6, 2011
    10,003
    Eastern Shore
    Just size once, you could be stretching them out when the handle is being lowered the second time around or the expander is dragging inside the neck when you turn the case.

    My over-achieving OCD seems to have taken over at the reloading station the past few days. Thanks for the guidance.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    It looks to me that it is not passing the Dillon as SAAMI compliant.

    The base needs to be flush with milled lower strip to be SAAMI compliant.

    I learned this with an AR I have with a tight chamber. Clandestine worked on the rifle and chamber is to spec. But if I load rounds to be flush with the higher portion, they do not chamber well and are hard to eject without firing. If I size to the lower step, they are fine.
     

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    Doco Overboard

    Ultimate Member
    Whats neat about those gauges is when you use one to determine how much impact a bolt has on a cartridge that you don't actually fire but has been run into the gun by its own volition then emptied from the chamber and reinserted into the gauge.
    Even a bolt action rifle that has a cartridge vigorously chambered then reinserted into the gauge can show some differences. A clever shooter will notice right away if your plotting your shots, its sometimes specific rounds that exhibit a higher degree of accuracy with speed and theirs a reason for it in some but not all rifle types and cartridge combinations.
     

    Seagrave1963

    Still learnin'
    MDS Supporter
    Feb 6, 2011
    10,003
    Eastern Shore
    Just size once, you could be stretching them out when the handle is being lowered the second time around or the expander is dragging inside the neck when you turn the case.

    Going to run another batch (100 cases) today with only one time through the press. Will let you know the outcome.

    Thanks (and Pinecone too) for the guidance.
     

    Seagrave1963

    Still learnin'
    MDS Supporter
    Feb 6, 2011
    10,003
    Eastern Shore
    Just size once, you could be stretching them out when the handle is being lowered the second time around or the expander is dragging inside the neck when you turn the case.

    Going to run another batch (100 cases) today with only one time through the press. Will let you know the outcome.

    Thanks (and Pinecone too) for the guidance.

    Zero case "fails" with the 100 this afternoon - looks like that was the trick.
     

    Seagrave1963

    Still learnin'
    MDS Supporter
    Feb 6, 2011
    10,003
    Eastern Shore
    Well, now at about a 30% case gauge failure rate. This is Lake City Match that was once fired. I had reloaded a bunch (~200) a couple of years ago using the Dillon Precision case gauge and had no issues in my Savage 10PC. These were run through the press just once (thanks again for the guidance). I gently cleaned the die as well as the Lyman gauge and am now wondering if either of those may be out of spec. Any suggestions or guesses?
     

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    Seagrave1963

    Still learnin'
    MDS Supporter
    Feb 6, 2011
    10,003
    Eastern Shore
    After cruising through the interwebs, I decided to see what would happen with these "failed" cases if I ran them through a small base die. Now they all "pass" which leads me to believe the Lyman case gauge has dimensions for semi-auto chambers. Is this a reasonable theory?
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    No, SAMMI specs for chambers and ammo are not action specific.

    It just means that rounds were fired in a large chamber, and with a standard base die, brass spring back kept them too large.
     

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