Technical question on trajectory!
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  1. #1
    Junior Member
    Join Date
    Oct 2020

    Technical question on trajectory!

    We are shooting a .300 RUM
    Zero at 200 yards.
    According to various ballistic calculators.
    At 500 yards it calculates a bullet drop of 32.4 inches.
    A custom elevation turret was ordered to all the correct specifications to a very reputable company.
    Gave ALL applicable data, velocity, bullet weight, BC, etc.
    Set 2 targets at 200 yards. The top one was exactly 32.4 inches above it.
    Turned the turret to 500 yards, fired at the bottom target.
    I was assuming the bullet would hit the top target, right on.
    Not on the paper and no idea where it's hitting.
    Am I making the wrong assumption, or is there a problem with the turret, or even the ballistic calculator data?
    Any and all responses would be appreciated.
    Thank you!

  2. #2
    Super Moderator Doom's Avatar
    Join Date
    Dec 2013
    South of the Mason Dixon Line
    Assuming the turret is correct and zeroed on the 200yd mark then Assuming in/100yd, the elevation is 32/5=6.4. At 200yd 6.4*2=12.8”. In MOA, 32/5/1.047=6.1 MOA, at 200yds 6.1*2*1.047=12.8”

    You should be able to duplicate this in you Ballistic Calc by setting the zero at 500yds and looking at 200yd rise.

    Drops are relative to line of sight, so you raise the line of sight 32” at 500 yds, At 200yds its less.
    Last edited by Doom; 10-09-2020 at 09:41 AM.
    "If we open a quarrel between the past and the present we shall find that we have lost the future.”
    Winston Churchill

  3. #3
    Super Moderator rkittine's Avatar
    Join Date
    Sep 2014
    Sag Harbor, New York
    I am not sure what bullet weight you are using, it's BC and design, nor the velocity you are shooting at. Give us those parameters and we can look into this more. What MOA is built into your scope mount.

    Last edited by rkittine; 10-10-2020 at 05:45 PM.
    Robert Kittine
    Sag Harbor and Manhattan, New York

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  5. #4
    Junior Member
    Join Date
    May 2016
    Mid-East Iowa
    Doom said it all. Take a piece of paper or cardboard and mark your 200 yard zero aiming point. Make sure that you have enough material above this point to show a hit ... say 18" more of paper or cardboard. Shoot to confirm your 200 yard zero. Then turn your turret to the 500 mark and shoot the same 200 yard zero aiming point. If the turret matches the information AND bullet the turret was design for there should be evidence approximately 13" above the first shot(s). Also, if the scope was properly mounted on the rifle, and the system wasn't canted when you shot, the 500 yard hole should be directly vertical indicating good tracking.


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