MARK 4 2nd Focal Plane range estimation.

Discussion in 'Long Range Hunting & Shooting' started by 5r milspec, May 26, 2010.

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  1. 5r milspec

    5r milspec New Member

    May 26, 2010
    I think i read something about this topic before on here and if it already exists can somebody please redirect me so I am not beating a dead horse over again. Haha.

    I use a .308 5r milspec with a mark 4-4.5-14-50 sfp with the TMR. My question is about range estimation with this scope. My understanding is that at 14x, 1 mil reading is true in the reticle. I was wondering if this is correct of the other power settings. Please confirm or deny.

    14x 1 mil reticle reading = 1 mil
    11x 1 mil reticle reading =1.27 mil
    8x 1 mil reticle reading = 1.75 mil
    5x 1 mil reticle reading = 2.8 mil
    4.5x 1 mil reticle reading = 3.1 mil

    The formula i use is
    taget in inches/36*1000 then divided my mils read= target distance in yards. I know the other formulas but this one is the one i use.

    So my example is this. 18 inch target reading 2.5 mils in reticle.
    1) 18/36*1000=500
    2) 2.5 mils in recticle * by 2.8mil (5x equivalent) = 7
    3) 500/7=71 yards.

    So the 18 inch target will be approx. 71 yds away. Is this correct or am I making a mistake with the power readings. I also use a vortex viper ffp so ranging is not a problem at any power setting. I know the easy answer is get a range finder but thats taking the fun outta it. I have a follow up question with hold overs but i wanna make sure i am doing this right with the 2nd focal plane reticle. The vortex is on a target range .223 gun that doesnt see more than 200 yds use so i seldomly use it for range estimation. Please respond. thanks.
  2. Skinny Shooter

    Skinny Shooter Well-Known Member

    Jul 25, 2002
    Hi 5r milspec, welcome to the forum.

    You want to confirm that 14x is the setting to use when ranging.
    10 Mils covers 36" at 100 yards.

    I checked my Leupold mildot scopes this way:
    Set up a 36" tall piece of paper at 100 yards.
    Put your rifle in a sturdy rest and set scope on a low magnification.
    While viewing the paper thru the scope, slowly turn the power ring till the full 10 mils of your scope cover the paper from top to bottom.
    That is from the bottom of the top thick post all the way down to the top of the bottom thick post.
    You may find that your scope covers 10 Mils before it gets to its maximum magnification.
    My 6.5 to 20 covers 36" on the "X" at the 12x setting.
    Be sure to write down where this spot ends up.

    I'd also suggest getting a mildot master: Mildot Enterprises Mildot Master Range and Bullet Drop Calculation Guide - MidwayUSA

    Mil Dot Riflescope Instructions - Rangefinding mildot reticle and mildot riflescope specifications
    Learn More About Mil-Dots in Rifle Scopes