Rangefinder Reticle
Saturday, February 13th, 2010Using Mil-Dot Reticles For Long Range Shooting
Many a hunter has passed up a clear shot at game because it was far enough away that he couldn’t estimate range accurately enough to appropriately compensate for bullet drop.
Several methods to accurately determine range are now available including optical and laser range finders but these involve another piece of equipment to buy, maintain, and carry. In recent years rifle scopes with range finding reticles have become available to hunters
at prices within reach of any budget. The mil-dot reticle is arguably the most accurate means of estimating range using a manual optical device.
The mil-dot reticle is based on the milliradian angular measurement system where a mil is an angle equal to 1/6400 of the way around a circle. A mil also conveniently equals a
movement or displacement of one yard at a distance of 1000 yards. Long used by the military for artillery and then for snipers where knowing an accurate range to the target is
essential, milliradian measurement is now readily available to the sport hunter in the form of mil-dot reticle rifle scopes.
The usual configuration for a mil-dot rangefinder scope is four dots evenly spaced on each of the small crosshairs with the center left clear for better aiming. The beginning of the thicker crosshair is one mill from the fourth dot making a ranging capability 10 mils in both the vertical and horizontal directions. The 1 yard at 1000 yards distance between dots will only be true usually at 10x magnification or the maximum magnification available but this does vary between scopes so be sure to read the instructions that come with your rifle scope.
Once you have your scope magnification on the proper setting (if yours is a variable power instead of a fixed power scope) all it takes is a simple formula to calculate distances.
(The Target’s Width or Height in Yards x 1000)/ The
Target’s Width or Height in Mils = Range in Yards
A useful alternative is,
(Object Size in Inches x 27.8)/Object Size in Mils =
Range in Yards
As you can probably already tell, a table of ranges by size and mils is going to be very useful and one of the best is a free download from Cheaper Than Dirt. It has target size in both inches and yards across the top with the number of mils spanned down the side. Where your two measurements cross in the middle is the range to the target in yards.
You will also have noted by now that while the formulas are simple and the table is more simple yet both require you to know the size of your target. This is a matter of quick and easy homework. It is matter of only minutes research to find that the depth of the chest of the average deer is 18 inches. If the deer you see in your mil-dot rangefinder rifle scope splits a mil-dot with his back and splits the second mil-dot down with his breast bone he is 250 yards away. Similar size information is just as easy and quick to find for anything from prairie dogs to elk to muskox.
Knowing the average size of your target game and determining the number of mil-dots spanned to calculate range is just the beginning of the usefulness of mil-dot rifle scopes. Because the mil-dot reticle measures not just size but also size at your target’s range it can be used to indicate hold-over to compensate for bullet drop and hold-off for wind drift or target
movement. Just as you need to know the size of your target to determine range you need to know the bullet drop table and the wind drift chart for your cartridge.
These are readily available at your ammunition makers web site or in the
back of any edition of Gun Digest. If you hand load your ammunition or if you’re just curious you can also enter the bullet muzzle velocity, ballistic coefficient, sectional density, and altitude into the calculator at the BigGameInfo web site and instantly have a table for
bullet drop and wind drift with ranges out to 1500 yards. Using the calculator I learned that at 6500 feet altitude my .375 H&H hand loaded ammunition has 3 inches less bullet
drop and 4 inches less wind drift (in a 10 mph wind) at 400 yards than when
shooting at sea level.
Using the mil-dots in your scope is much faster than adjusting scope knobs and you don’t forget how many clicks back you need to re-zero your scope. Say, for example, you know you have zeroed your rifle at 200 yards, it hits 3 inches low at 250 yards and 8 inches low at 300 yards etc. Then in the previous case where the deer is 250 yards away according to
your new range finding scope the table will also tell you that 1 mill at 250 yards is equal to 3 inches and you just need to hold the first mil-dot below the scope center on the aiming point and fire away. For my .375 H&H a 10 mph direct crosswind would move the bullet 18 inches at 400 yards and the mil-dot range estimation table indicates I need to hold 1½ dots into the wind. Is that simple or what? And all without having to carry along any extra hardware.
If you’re tired of passing up longer shots or missing game at extended ranges a mil-dot range finder rifle scope may be your answer. They are no longer overly expensive, they’re easy to use, and with a bit of practice are extremely accurate. A mil-dot scope could be the
difference between an empty freezer or a full one. What are you waiting for? Scopes with mil-dot reticles suitable for everything from black powder guns to big-bore magnum hunting rifles are available for any budget. Get yours todayat www.rangefinderriflescopes.com!
About the Author
Steve Woodruff has hunted for forty-five years. A Michigan native, he most liked rifle scopes
light gathering powers. After moving west Steve learned to appreciate range finding
reticles and scopes with built-in laser range finders. See what he has for you at http://www.rangefinderriflescopes.com.