Long-term springback on sized necks?

Discussion in 'Reloading' started by tlk, Apr 20, 2011.

  1. tlk

    tlk Well-Known Member

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    Apr 11, 2008
    Something odd: I pulled out some cases that I had annealed, neck sized three months ago to reload. These cases were confirmed at .306 ID neck with a pin guage at the time.

    Last night I pull them out to reload and do a double check on the dims - the pin gauge slips around in there pretty good instead of a slight drag and an "air piston" pushback effect when I cover the primer hole and press down on the pin gauge in the shell. This is a measurement that I am fairly OCD about so it stood out. Wasn't .307 or anything, but it was a noticeable change.

    Is this normal over time? Would there be any real effects on neck tnesion with a loaded round?

    Thanks
     
  2. ken snyder

    ken snyder Well-Known Member

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    Jul 26, 2010
    I've noticed that pin gauging soft materials is not very repeatable, After the first time it is performed on brass. The gauge itself can enlarge diameters ( from slight interference to a slip fit), particularly when done by hand. Temperature: cold brass, warm pin and then the other way around can account for perhaps as much as .0005 in feel. other than slight oxidization as a friction modifier you still have really close to the same hole that you measured originally. The big culprit is doing it twice with a long interval between measurements and doing it by feel!
     

  3. loaders_loft

    loaders_loft Well-Known Member

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    Feb 11, 2008
    Probably just a temp change, if you are like me, loading in the garage. It was cold in january...