New powder lot - load tuning

Discussion in 'Reloading' started by bowhunthard, Feb 16, 2009.

  1. bowhunthard

    bowhunthard Well-Known Member

    Sep 5, 2008
    I was wondering if anyone has any experience tuning between powder lots. I have switched powder lots of Varget, and was wondering if there are any shortcuts besides re-testing?

    I was theorizing, and wondered if barrel harmonics were the key to accuracy? If this is so, producing the same harmonics would produce the same accuracy, right? Wouldn't the velocity be the key to barrel harmonics? Now if I could chronograph the loads and get the new powder lot to reach the same velocity as the old lot in the same temperature, wouldn't I have minimum load tuning to do?

    Just my pet theory, if anyone knows anything about this, if you could let me know.

  2. J E Custom

    J E Custom Well-Known Member

    Jul 29, 2004
    That is exactly how I do it but I also start with cases with the same weight/volume
    and load the same powder charge and adjust up or down to get the same 5 shot
    avg. velocity.

    If the ES and SDs are the same you will be very close.

    But don't be suprised if you still have to adjust a little but it will save time and some times
    the different lots shoot better.