05/31/2009

 Law Enforcement Firearmswith Richard Fairburn

# Product Review: The Mil-Dot Master

First developed and deployed by the United States Marine Corps, the Mil-Dot reticle has become a “must have” feature for many police and military snipers. The dots on a Mil-Dot reticle can be used as secondary aiming points for distances beyond your zero point, or the dots on the horizontal wire can be used to hold off for windage allowance or lead on a moving target. But, the original design intent was for rangefinding.

If you do a little research on the Internet, you will find several values for the “Mil,” which is short for Milradian. Originally, a “mil” was 1/6400th of a circle, which allowed for more precise artillery fire than the traditional degrees on a compass (there are only 360 degrees in a circle). Even today, an Army mil is slightly different from a Marine mil. But those distinctions become meaningless for our rangefinding uses. Most systems standardize the Mil as equivalent to 3.6 Minutes-of-Angle (MOA), the reticle adjustment system used on most rifle scopes. A Mil is also expressed in a ratio of 1 to 1000. In other words, if one Mil matches the size of a one yard target, that target is 1000 yards away. If the target matching the one mil measure is only 1 foot in size, it would be 1000 feet away (333.33 yards).

So, to use the Mil-Dot system to determine the range to your target, you must know the size of your target. Then, you have to do some pretty serious mental arithmetic to run the numbers and output the distance in yards (or meters). I prefer scope reticles calibrated in Minutes-of-Angle because a MOA is about 1 inch at 100 yards and I can work those numbers in my head. But, about 95+ percent of the rifle scopes with a rangefinding reticle use one calibrated in mils.

If you’re confused about how to calculate range with your mil reticle, there is an easy answer - the Mildot Master. This handy device works like a simplified slide-rule to convert target size and mil measurements to distance in less time that it takes to say it. The only secret to using the Mildot Master is to get a very accurate measurement of your target on the mil scale (dots or lines).

Let’s say you’re on a SWAT callout and are covering the front window of a residence. The battery went dead on your laser rangefinder, so you compare your mil reticle to a known target (see list below), such as a cinder block in the house foundation and note that two mil graduations perfectly match the 16 inch length of the block. You set the 16 inch target size line on the Mildot Master to the 2 Mil reticle line and you read a distance of 222 yards.

Without the Mildot Master, you would need to run the following calculation: the size of the target in yards (16 inches/36 inches = .44444 yards) X 1000 / Mils. So, a 16 inch cinder block = .44444 yards, times 1000 = 444.44, divided by the # of Mils that match the target (2) = 222.22 yards. If you can do that in your head, you should be a rocket scientist, not a cop. A digital calculator will easily calculate the numbers, of course, but the Mildot Master is faster and easier for me. The Mildot Master is small and handy (about 3x6 inches), made of weatherproof material and can deliver answers in either yards or meters. Another window on the calculator will convert bullet drop to MOA for scope adjustments and a scale on the reverse side can be rigged with a weighted string to measure range slope and estimate the gravity distance needed to correct for steep shots.

A Mildot Master should last you a lifetime unless you misplace it or another shooter snitches it from your bag, so the \$30 cost is a bargain in simplicity. You can get a Mildot Master from many equipment and training vendors or directly from Mildot Enterprises:

Mildot Enterprises
P.O. Box 6585
Oak Ridge, TN 37831

Phone 865-483-6620

www.mildot.com

Handy target sizes:

Cinder Block 8" high by 16" long Household Brick 2.5" high by 8" long
License Plate 6" high by 12" long House Doors (single - average) 79" high by 31" wide
Doorknob Height 36" Average Man (5'9" tall) 69"
Average Human Head 6.5" wide Average Human Head (hairline to chin) 10" tall
Average Chest Thickness 12" Average Torso (across shoulders) 20"