Mil-dots, EVERYTHING you want to know.

[Tomcat088]

Ok, so I decided to do a post regarding mil-dot reticle rifle scopes to help some people out with learning how to range and use hold over with them. Please keep in mind that you can find a great deal of this information at http://www.mil-dot.com . A good place to apply some of what you learn at the end of this is a simulation (not a game) called shooter ready. You can find it here http://www.shooterready.com/lrsdemolow.html .

I’m not going to get into great detail about the measurement of the system or why it works, if you’re interested in that, you can find it on that website or other places by searching of “mil dot angular measurement.” Basically, what you need to know is that mil’s are not a fixed measurement, they are an angular measurement that changes with distance and what scale you’re using. This sounds confusing, but basically a mil equals 1 yard at 1,000 yards, 1 mile at 1,000 miles, 1 meter at 1,000 meters, 1” @ 1,000”, some of you get the idea. It is NOT necessarily metric, but just because it is based on a 1,000 system, it does translate fairly easily to that. Either way, it’s an angular measurement; mil stands for milli-radian (radians being angular).

Reticles
Ok, now to get down a bit more to application…..

FIRST you need to know what type of mil dot scope that you have, there are quite a few variations of mil dot scopes, reticles, tactical milling reticles, etc. Most scopes that people buy are Second Focal Plane reticles, this means that your reticle will only accurately judge distance and/or hold overs at one predetermined power (this could be 10x or any other magnification setting as determined by the manufacturer). The way that you can determine if your scope is a First Focal Plane, or Second Focal Plane reticle is to watch the reticle as you zoom in and out. If the reticle appears to get larger (not just the object you’re viewing, but the reticle), then you have a First Focal Plane reticle; IF the reticle stays the same size, but the target gets larger then you have a Second Focal Plane scope. The difference is that with a FFP (first focal plane) reticle, you can range at ALL magnifications, with the Second Focal Plane Reticle, you can range only one predetermined power that is determined by the manufacturer. Sometimes this is the highest power, but on some higher powered scopes, manufacturers sometimes use a lower power so that you don’t have to try to mil at 16x; so they may use 10x or 12x, etc. You have to do the research on your scope to find out, or physically go measure (the best way) to know. For fixed power scopes, you do not have to worry because it only has one magnification to mil with and this should be accurate. If you are interested in finding out EXACTLY where your scope ranges properly, there’s a wonderful paper by Lindy from sniper’s hide here:

http://www.arcanamavens.com/LBSFiles...ScopeChecking/ .

Ok, next I’m going to now talk about some differences in mil-dot reticles. (I actually use a Generation II mil dot reticle, which has mil dots, and then it has hashes in between the mils which represent ½ mil.) We will be looking at the standard mil dot reticles; which there are basically 2 types. The standard mil dot reticle (or Army reticle) as some people like to call it, has ROUND mil dots and looks like this.


The U.S. Marines use a mil dot reticle that is slightly different and has “oval” or “football” mil dots and will look like this.



Neither of these reticles is superior to the other, they are just different. When you are ranging with mil dots, there are some fairly simple formulas that you will have to remember, along with what the marks in your reticle signify in terms of measurement.

In order to range a target with your reticle, you need to know a few things. You MUST know the height of your target. There are several formulas that I will be posting, so this can be the height of the target in meters, yards, or inches; it will all depend on which formula you would like to use. Either way, you must know a height that is pretty close to the actual height, so that you can use the angular measurement of the reticle to determine the distance to the target. The other thing that you need to know is the measurements of your reticle. With the “Army” reticle (round dots) these will be your measurements:


From the center of one dot, to the center of the other is 1 mil. From the inside edge of one dot to the inside edge of the other dot is .8 mil’s. From the horizontal crosshair to the inside edge of the first dot is .9 mils. Obviously the optical center between the 2 dots is going to be .5 mils. The mil dot itself is roughly .2 mils (actually .22), so from the center of one dot to the edge of the next is also .9 mils. When you get better at using the mil dot reticle and judging distances, you will actually start to look at finer measurements like this:



Now with the Marine mil dot reticle (or ovals), the measurements will be slightly different, and your measurements will be like this:



From the center of the oval to the center of the next oval is still 1 mil. From the inside of one dot to the inside of the next dot is .75 mils. The optical center between these 2 dots is also .5 mils. From the crosshair line to the edge of the first mil is 7/8’s mils, or from the center of one mil dot to the inside edge of the next mil dot will also be 7/8’s mil. The mil dot itself is actually .25 mils.

Ranging
Okay, so now you know the measurements of your reticle, what power it’s actually at, and the height of your target (either from measuring some specimens, or just looking it up). Now you need to go prone or get on a bench, and hold VERY stable. It doesn’t really matter exactly how you hold the reticle, as long as you know your measurements along it. You can start with crosshair post, or the center of one of the dots. If you can’t make it be dead on mils, or dead on in the center, you might try adjusting your point, so that you can use the ¾ mil spots, or some others. This is when you are only in the beginning phases, to kind of help you get a feel for it. As you get better, you’ll be able to use your eyes to judge the center, and then just the center of that center. Depending on your distance and magnification for your scope, you should come up with a number, maybe something like .75 mil’s, or maybe it’s 1.75 mils (it doesn’t matter) as long as you have a number that you feel pretty confident in and have double or triple checked. So what do you do now with this measurement?

This is where the formulas are necessary and come in handy. There are LOTS of formulas, and which one you use really doesn’t matter, as long as it’s something that you can remember, or come up with a number that’s useful to you. I will list LOTS of formulas, so that you can choose the one that best fits you.

Distance to Target(Yards) = [Height of Target (Yards) * 1000] / Image Size(mils)

Distance to Target(Yards) = [Height of Target (Inches) * 27.778] / Image Size(mils)

Distance to Target(Meters) = [Height of Target (Inches) * 25.4] / Image Size(mils)

Distance to Target(Meters) = [Height of Target (Meters) * 1000] / Image Size(mils)

Distance to Target(Meters) = [Height of Target (cm) * 10] / Image Size(mils)

Now you simply need to plug in your information to get your distance.

Say I am shooting at a silhouette shaped target that is 36” tall and appears to be 1.5 mils in my reticle, and I want the distance in yards. I am going to use the formula for inches because I know the target’s height in inches. I would put in my calculator (36 x 27.77)/1.5 , to get an answer that the target is approximately 666.48 yards away. If I was doing this calculation with a height of target in yards and want the distance in yards, I’d plug in (1yard x 1,000)/1.5, to get an answer of 666.67 yards to target. The formulas will all work, it will just depend on what you know the target’s height in, and what kind of answer you would like to get (yards or meters). So now you know the distance to your target.