ATTENTION all who use MOA or MIL reticles for back up ranging.

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Michael Eichele, Apr 20, 2009.

  1. Michael Eichele

    Michael Eichele Well-Known Member

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    To all who use MOA or MIL reticles for back up ranging purposes.

    I was updating some software this morning and came accross some discrepancies. I am sure some of you guys know this. I am also sure many do not.

    The standard for mil ranging is target size in inches * 27.778 / Mil value = range in yards.

    The standard for MOA ranging (according to Nightforce and their most recent reticle booklet) is target size in inches / MOA value * 100 = range in yards.

    This standard is not 100% accurate due to the inch/MOA conversion.

    An example is an 18" target that takes up exactly 1 mil = 500 yards.

    The same target taking up 3.44 MOA (same as one mil) = 523 yards using the 100 as a constant.

    The same formula except using 95.5 (which is 100 / 1.047) for a constant instead of 100 gets you to 500 yards.

    I talked with Ken at NF this morning and he confirmed that 95.5 was in fact the most accurate number to use. They use 100 in their information booklet to "simplify" the formula for the user.

    Hope that helps somebody. Who knows, maybe I am the last one to figure this out!
     
    Last edited: Apr 20, 2009
  2. davewilson

    davewilson Well-Known Member

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    would that make .955 moa for an inch at 100 yards?
     

  3. kraky2

    kraky2 Well-Known Member

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    YUP!!
     
  4. Michael Eichele

    Michael Eichele Well-Known Member

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    And they say the Mil system is complicated! :D
     
  5. Limbic

    Limbic Well-Known Member

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    painfully obvious..... now that you've explained it.
     
  6. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

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    Thanks for pointing that out Michael.

    I'm a firm believer in verifying scope markings whether they're in the reticle or click values on the turrets. Too many targets are missed because the scope adjustments or reticle markings are assumed to be as advertised, or the shooter misunderstands the advertised value.

    My advice is to verify whatever method you use to correct for drop, no matter how expensive the scope.

    Sights are the critical link between your knowledge of the trajectory, and what you do to correct it. If that link is weak, targets are missed no matter how precise everything else is.

    -Bryan
     
  7. Buffalobob

    Buffalobob Writers Guild

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    One of the fundamental issues of optical measuring equipment is calibration. If you should ever try to duplicate Milikan's oil drop experiment for which he won the Nobel Prize in physics you will find you must calibrate the optical equipment. My lab partner got a A for her report and I got a B for mine because mine was not "neat". She had a typewriter.


    Advanced Lab - Millikan Oil Drop:Experiment