Thought the attached would be handy. As long as you know the height or width of the target, you just size it in MOA or MIL and look up the distance in the appropriate box on the chart.
Distance in yards.
Tables are fine, but I prefer just knowing the following algorithm: Approximate Range = (size of target in inches) / (size of target in MOA).
Then compute 10% of the Approximate Range, and halve that, to get the 5% correction.
Then, estimate corrected Range as Approximate Range minus the 5% range correction.
Example: Target of 21 inches, 7 MOA subtended. Approximate Range = 21/7 = 3 hundred yards.
10% of 300 yards is 30 yards.
Half of that is 15 yards.
Range = 300 - 15 = 285 yards.
Or, you can just stop at Approximate Range if you are in a hurry. But, to win an UD (Unknown Distance) speed contest for ranging, be sure to do the 5% correction.
No tables needed. Mental math only. BSZ. Done. YMMV.
But, if shooting targets much smaller than 4 MOA, use the table. Or, just use the calculator on your Smart Phone.
And, if you want to do ranging in mils, mentally, then just remember that 0.1 MIL is 1/3 MOA. Convert the subtended MILs to MOA, and then use the same algorithm as above.
And, if you can see your misses, splashing dirt, or punching holes at 25 yards, just measure the offset from center of target to splash or hole in MILs, dial in the appropriate number of 0.1 MILS, and you're DONE. YMMV. No math needed.
With a MIL-dot scope, you don't need to post a target. You can just use a leftover target left by a previous shooter at the range.
â€" gb
The math *is* fast and easy to do in your head with a little practice. MOA is intuitive and simple if you do all your work in yards - otherwise an extra conversion is needed for meters.
The great thing about MILs is that the math is the same regardless of what units you're using.
RANGE in (unit) = target size in (same unit) X 1,000 (i.e. move the decimal 3 places right) / target size in MILs.
No additional conversions needed.
I.e. you know that an adult western coyote is typically a half meter high at the shoulder, you're glassing him at 2 MILs...
.5 x 1000 = 500 / 2 = 250M
True!
And, you can approximately convert meters to yards by just adding 10%.
So, 250 m is about 250 + 0.1x250 = 250 + 25 = 275 yards.
(The exact value is 273.4 yards, using 39.37 inches per meter.)
Mental math. Easy.