Fieldcraft This is how you do range math Check it out

J.Boyette

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    Got your thinking cap on?

    If not go get it.

    This is how you do range math Check it out.

    There is 91.44 meters to every 100 yards. So if I wanted to do the math in my head its simple.

    I take the 9 from the 91.44 as a constant.

    I go 200yds" x 9 = 18 move the last 0 in 200 to the 18 and get 180meters

    This is very close and will still get a hit on target. the difference between 90 and 91.44 is not much.

    Here are some more yards to meter range math:

    300yds" x 9 = 27 move the last 0 in 300 end of 27 and get 270meters

    Going from meters to yards is the same game just a different direction.

    300 meters" x 9 = 27 drop the two 00 in and insert the 27 for 327yds

    400 meters" x 9 = 36 drop the two 00 and insert the 36 for 436yds

    Granted you are off by 1 or 2 yards but it gets hits anyhow

    So on it goes

    John
     
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    OregonShooter

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    Re: This is how you do range math Check it out

    That's like "Yoda, top secret squirrel stuff right there!"

    Thanks!
    smile.gif
     

    JB5812

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    Re: This is how you do range math Check it out

    I've always been fascinated by these two simple formulas for some reason. Coolest thing you can do in your head that quick IMO.

    Josh
     

    CoryT

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    Re: This is how you do range math Check it out

    Could I just stick with + or - 10 percent? I'm math challenged.

    300 meters + 10% = 330 yards

    600 yards - 10% = 540 meters

    Seems close enough for government work
    wink.gif


     

    Gordon Nettleton

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    Re: This is how you do range math Check it out

    John, my wife owns a Knit store and most of the yarn comes in meters because it is from England and they use that little trick all the time for guage's and estimate inventory. It works guys, best cheat sheet next to sitting next to Rebecca Burnett in Chemistry in High School. She wrote real big.
     
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    Luke

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    Re: This is how you do range math Check it out

    John: Do you have any quick technique for if it's a between number, say 756 meters? You can still use the same process and then just add back on the last two numbers you dropped (56) and it's close, bot not perfect. Thoughts?
     

    Luke

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    Re: This is how you do range math Check it out

    Cory: I too find the adding and subtracting 10% easier. Just clicks on my head better. It's not perfect but close.
     
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    J.Boyette

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    Re: This is how you do range math Check it out

    Luke,

    Never really tryed what you are asking for. I use this more for a range issue.

    Like if I shoot on a 100m range I know to dial 109yd dope and such.

    John
     

    Luke

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    Re: This is how you do range math Check it out

    I gotcha John. The 10% rule works pretty well for random numbers, give or take 5-10 yards/meters.
     

    nordmnman

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    Re: This is how you do range math Check it out

    Maybe I am understanding this right but going by J's formula it seems like you could just minus instead of add and get the reverse as going from meters to yards.

    756 7x9=63
    756 - 63 = 693 yards
     
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    J.Boyette

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    Re: This is how you do range math Check it out

    mnhunter,

    If that works for you have at it bro.

    John
     

    THibben

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    Re: This is how you do range math Check it out

    My Boyette,

    '100m range using 90 yard dope' - 'cough', how about 110yard dope?
    wink.gif


    English
     

    J.Boyette

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    Re: This is how you do range math Check it out

    English,

    Roger that, I was thinking the other way when I typed that. Thanks alot for the catch.

    John
     

    THibben

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    Re: This is how you do range math Check it out

    John,

    Typing is different from shooting, you'd know on the range 'cause instictivly you'd need more 'up'

    Have a good Christmas.

    English
     

    Cheese

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    Re: This is how you do range math Check it out

    Great job John.
    Now do it for MOA vs MIL Dots.
    grin.gif
     

    J.Boyette

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    Re: This is how you do range math Check it out

    Scott,

    Thats easy.

    John
     

    Cheese

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    Re: This is how you do range math Check it out

    I mean out loud bro.
    I have been asked so many times to put it in writing.
    It's got to be here in a thread somewhere.
    Merry Christmas to you and your family.
    See ya' at SHOT!!
     

    Lindy

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    Re: This is how you do range math Check it out

    <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Now do it for MOA vs MIL Dots.</div></div>

    Get scopes which adjust in the same units the reticles are graduated in. Converting from one to the other sucks, and the time it takes might get you killed if you shoot on two-way ranges. If you only shoot in competitions, it might cost you a shot. Don't do that.
     

    Cheese

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    Re: This is how you do range math Check it out

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Now do it for MOA vs MIL Dots.</div></div>

    Get scopes which adjust in the same units the reticles are graduated in. Converting from one to the other sucks, and the time it takes might get you killed if you shoot on two-way ranges. If you only shoot in competitions, it might cost you a shot. Don't do that.
    </div></div>

    Tell me about it.
    I wasn't on a two way range, however I was spotting in MILS for a shooter that had a MOA scope. What a pain in the [email protected]#.
    That will always be in the check list from now on.
     

    biggestguns

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    Re: This is how you do range math Check it out

    If you want exact math you could always use this.
    yds * 0.914 = m
    or
    m * 1.094 = yds
    I just carry a rite in the rain field book. (www.riteintherain.com/tact.html) This and rite in a simple times table is easy if you still remember how to do the math.
     

    Parker-Hale Mike

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    Re: This is how you do range math Check it out

    That's a good formula to know. My log book has a solar powered calculator in it at all times, I also have the 91.44m-100y formula written down incase my calculator and murphy meet up.
     

    Novadesigns

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    Re: This is how you do range math Check it out

    This is a nice little device for simple calculations but there is one concern, the deviation is cumulative. That means that while you're only off my 1.44m at 100 yards, by the time you're out at 600 yards you're now off by nearly 9 meters. That can easily mean the difference between a hit and a miss. Its good to get you in the ball park... but I would recommend remembering that 1.44 <span style="font-weight: bold">(round it up to an easy 1.5)</span> meter difference and mentally multiply it times the first number distance and add it back in to get closer.

    For example: 600 yards x 9 = 54 add 0 to get 540 meters <span style="font-weight: bold">PLUS</span> 1.5 x 6 (600 yrds) = 9 + 540 = 549 meters... just about right on target, a 0.25 meters over rather than 8.46 meters short.

    I carry a small calculator as well. Its easier.
    wink.gif
     

    sig fan

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    Re: This is how you do range math Check it out

    2.54cm=1 inch

    36 inches x 2.54= 100 cm

    100cm / 2.54= 36 inches

    Just multiply by 2.54 to get cm and divide by 2.54 to get inches.

    Yeah, not to quick in the battlefield. But if you've got time and a calculator.
     

    MarcC11B

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    Re: This is how you do range math Check it out

    BTT...because I used the search for three f*cking hours trying to find this post!
     

    MitchAlsup

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    Re: This is how you do range math Check it out

    100 yards is 91.44 meters, sure, but what is the multiply by 9 stuff. It is far easier to subtract from 10-1 to get 9.

    x00 yards is x00 - x0 meters

    Thus, 600 yards is 600 - 60 = 540 meters and you don't even have to understand multiplication, just subtraction.
     
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    CoryT

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    Re: This is how you do range math Check it out

    All I can say is if 9 meters causes a miss at 600, you need a cartridge that at least starts supersonic, or a target bigger than 1/4 MOA.

    How, pray tell, does one range a 1/4 MOA target at 600 +/- 9 meters anyway?
     

    tarkio

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    Re: This is how you do range math Check it out

    I'm new here but I have a way to calculate things like this fairly quickly in ones head.

    The question is how to do a conversion with where 91.4m = 100y

    For me I simply look at the difference going meters to yards by adding (10%)-1%

    In other words if I need to convert 756 meters to yards:

    756 + 10% (75.6) which makes

    831.5, more or less

    then I subtract a tenth of what I just added (75.6) or 7.5, more or less

    So that makes it 831.5 - 7.5 or

    824 yards.

    Which gets you within a couple yards.

    I'm not good at describing this but I essentially add 10% and then subtract a tenth of what I'm adding.

    Does that make sense?
     

    tarkio

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    Re: This is how you do range math Check it out

    To go the other way, yards to meters, I subtract 10% and then add a tenth of what I just subtracted.


    756 yards = ? meters

    756 - 10% (75.6) = 680.5

    And then add 10% of 75.6 (7.5)

    680.5 + 7.5 = 688 meters, more or less.

    Hope this isn't too confusing.

    The official conversion would be 756 * .9144 = 691.

     

    mp40sw

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    Re: This is how you do range math Check it out

    So why the hell did I just spend $500.00 on a range finder!!

    jk, good post, I would have had 10 typos in a post that long.

    Good Job!!
     

    marduk185

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    Re: This is how you do range math Check it out

    this is sorta neat but why would i find myself converting measures like this? dont yall just do your dope in one or the other and stick with it?
     

    camomallninja

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    Re: This is how you do range math Check it out

    what ever happen to 27.77?
    and where is your milldot calculation?

    example

    target size 18"
    18x27.77=499.86 or to round off 500
    target covering 2 mills
    500/2=250 yards away

    it's target size multiply by 27.77 divide by milldot covering target=range

    ok I read your post again you are going from yards to meters using 9
    got it that's kind of cool.
     

    J.Boyette

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    Re: This is how you do range math Check it out

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: camomallninja</div><div class="ubbcode-body">what ever happen to 27.77?
    and where is your milldot calculation?

    example

    target size 18"
    18x27.77=499.86 or to round off 500
    target covering 2 mills
    500/2=250 yards away

    it's target size multiply by 27.77 divide by milldot covering target=range

    ok I read your post again you are going from yards to meters using 9
    got it that's kind of cool. </div></div>

    If I was mil'ing a target using 27.778 would only work for yards only.

    or

    Width or height of target (yards) X 1,000 divided by the mil size of the target in the reticle = range in yards.

    IF I was mil'ing a target and wanted meters I would use:

    Width or height of target (meters) X 1,000 divided by the mil size of the target in the reticle = range in meters.

    Width or height of target (in inches) x 25.4 divided by the mil size of the target in the reticle = range in meters.

    Your first question does not pertain to this post.

    Sorry.

    John