## Rangefinding Made Simple## Mildot UsersWhat is a mil? 1 mil of angle covers one yard at 1000 yards. 3.6" at 100 yards. Or 1 meter at 1000 meters. Some scopes have a reticle graduated in mils. The number of inches covered by the mildot is a measure of range. Lucky metric users know that 1 mil of angle covers 1m at 1000m. 10cm at 100m. Or 4" at 100m, 12" at 300m. I learned to shoot in the Army on metric ranges, so I estimate range in meters anyway. One mil on your reticle covers 5/6 of a 12" target at 8x magnification. What is the range? How many scope clicks? I made up the "MilRange" system to avoid mental arithmetic.
Here's the table for the second example. See if you can do it by yourself.
The example is .308 Winchester, 175gr, 2740 fps, BC 0.46, 100m zero, 10mph crosswind at 90 degrees. But you can print a table for any load you like. -
**MOA** A minute of angle is a one inch at 95.55 yards, or 1.05" at 100 yards (see below for the exact value). Most people say "one inch at 100 yards" for the sake of simplicity. Scope sights usually have adjustment in 1/4 MOA clicks, so if your zero is off by 1" at 100 yards, that would be 4 clicks to adjust. Off by 1" at 50 yards, 8 clicks. If the scope has 1/2 MOA clicks, off by 1" at 100 yards would be 2 clicks to adjust. That's all there is to it. Some scopes allow you to set your zero, and then adjust the scope knobs for elevation and windage, You get elevation and windage from a ballistics table. If the drop is 2" at the target's range, you can aim 2" high instead of adjusting the scope. You can memorize the bullet drop at 100, 200, and 300 yards for your rifle and ammuntion, so you can make the necessary adjustment. It's worth knowing the amount of windage for a 10 mph wind at these ranges too. 10mph means loose papers blowing around and small branches moving. It also means at right angles to the firer. If the wind is at an angle, you guesstimate what proportion of the wind is at right angles to the direction of fire. The wind*accelerates*the bullet in the wind direction. So doubling distance*more than*doubles wind deflection. This makes is long-range shooting difficult, you may have to get closer to the target if it is windy.
**Nerd Alert:** Take a scientific calculator. Type in 1, TAN, multiply, 60, equals. The answer is 1.04730389569305514590773371318367, which is the number of inches covered (or*subtended*) by a minute of angle (MOA) at 100 yards.
## Mil-Ranging on non-Mildot ScopesYou can use a non-Mildot scope to estimate range using this program. Say your fixed 4x scope crosshairs cover 0.4" at 25 yards. Run the program with different scope magnification numbers (5.6x in this case) until the MilRange at 25 yards is 0.4" (or 4" at 250 yards). So now you print the table, and you can use it to estimate range, pretending the crosshair width is a Mildot. If your scope is adjustable, you have to use the same magnification for when you estimate what your crosshairs cover, and when you estimate range with your printed table. Otherwise it doesn't work. Don't use a scoped rifle to estimate range on anything you are not prepared to shoot. You can carry a $25 compact scope in you pocket and use that for ranging in the field. Free Ballistic Simulator Software updated Sunday August 01 2010 at 11:43am. Email Frank Clarke About Frank Clarke |