More trajectory help needed

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by 4ked Horn, Oct 10, 2007.

  1. 4ked Horn

    4ked Horn Writers Guild

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    My bro and I are trying to stretch out the known and tested trajectory for his .338 win mag. We went to the desert and shot a 12" sq gong repeatedly at 500, 600 and 700 yards so we are very close to the numbers listed below for those ranges. the distances of 100-500 yards were shot and measured on paper so those drops are a little more accurate still. But for some reason I can't get any ballistics program to come close to what we are observing. Consequently I am unable to put together a decent drop chart for him so if he sees his elk at say, 638 yards we don't have a good number to click to on the scope.

    It would be a huge help if someone would email ( 4kedhorn@gmail.com ) me a drop chart in 20 yard increments with a 100 yard 0 and a 10 mph full value cross wind that makes some sence of the drops we gathered in the field. If it is not too big of a pain itwould be very appreciated if the chart also had drops at 4000 feet elevation since we will be hunting at that altitude even though we tested at 2800 feet.

    Cal .338
    Weight 250 gr
    Sierra sbt
    bc..565 @ 2500 fps and above
    .563 between 2500 and 2000 fps
    .550 between 2000 and 1600 fps
    .537 @ 1600 fps and below

    MV averaging 2575
    Scope height 1.625"
    Altitude tested 2800'
    Temp 60 deg

    Drops we used in moa rounded to 1/4 moa
    100=0
    200=2.25
    300=4.5
    400=7
    500=11.5
    600=16.75
    700=19

    Thanks for your help.
     
  2. AJ Peacock

    AJ Peacock Well-Known Member

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    Email sent with a couple excel files.

    Didn't match your drops exactly, but got pretty close.

    AJ
     

  3. 4ked Horn

    4ked Horn Writers Guild

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    When we shot the first set of ranges from 100 to 500 the drops were not following a predictable arc at 400 yards and this time when shooting from 500 to 700 we had the inconsistant drop at 600.

    We will certainly be reshooting this distance on paper before pointing it at game. Thanks for the spreadsheet. I really need to get the exbal program. I have heard it will let you enter field tested drops and adjust the calculations to predict the drops for your particular circumstances.