This simplified approach to Mil Dot scopes will help hunters put these tools to good use.
To figure out what a mil dot scope is, first we must figure out the origins of the term “mil.” Contrary to popular belief, a mil dot reticle is not an acronym or shortened version of “military.” Instead, MIL is a shortened version of the term mil radian.
What is the difference in MIL and MOA? MOA stands for “minute of angle.” Minutes are just a smaller measurement of a degree. A minute of angle is also a measurement of an angle within a circle, just as milliradians are. However, they differ in size, with mils being the larger of the two. Some experienced shooters think that minutes of angle are a bit easier to understand than mils. This writer has learned that MIL scopes with MIL reticles are faster to use.
Remembering back to our high school geometry classes, we know that there are 360 degrees in a circle. As the circle grows larger in circumference, the number of degrees doesn’t change, but the distance from one degree to the next along the circle does increase. Remember the terms “minutes” or “minutes of angle”? Well, these degrees on a circle are also divided into smaller units called minutes. Each degree is divided into 60 minutes. When you get to 100 yards, the angle of one minute is approximately, but just a hair over, one inch. For easy reference, if we shoot a group at 100 yards and the centers of the two farthest bullets measure one inch we call that a minute-of-angle group. When you move to 200 yards, a 2-inch group is still a minute-of-angle group. This holds true as the yardage increases or decreases.
One mil of angle is approximately 3.6 inches long at 100 yards, or very close to 3.5 minutes of angle. Most mil dot scopes are calibrated to this value at their highest magnification, if they are a variable. So, if your bullseye is 3.5 inches in diameter and 100 yards away, it will touch the centers of any two dots next to each other. If it appears only half that size through the scope (from the center of one dot to half the distance to the next center) your target must be about 200 yards away, etc.
To use this optic in its range-finding application, you have to know how to apply the correct mathematical formula, plus you have to know the approximate size of your target. For instance, if your target is 72 inches tall, its corresponding height is 20 mils at 100 yards. At 1,000 yards a 72-inch-tall target will appear two mils tall. In practice, it’s much simpler than trying to explain it in writing. Military and tactical-type scopes have mil dots on both horizontal and vertical crosshairs so they can measure height as well as width of an object to estimate range. In addition, the mil dots on the horizontal cross hairs can be used to adjust for windage.
Mil Dot Riflescope in Use
As a secondary function, the mil dots on the reticle can be set up as aiming points to compensate for holdover and wind drift, when you combine it with a laser rangefinder. With particular bullets driven at a specific starting velocity they line up nicely with the mil dots at 100 yard increments. The charts below show the comparative drops at 100-yard increments.
In practical use, if you have a starting velocity of 2,800 fps and a B.C. of about .500 the drop values at each 100-yard increment line up well with corresponding dots and post between 300 and 700 yards without dialing in additional drop. A shortcut for distances beyond 600 yards can be achieved by dialing in drop from the 4th mil dot instead of from the crosshair. This will save you time and many clicks in adjustment.
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