Range Estimation | A Key Skill in the Sniper’s Toolbox

 Whether you’re in the military, an avid hunter, or preparing for the zombie apocalypse, knowing and understanding range estimation is paramount.

That’s why we’ve decided to put this handy-dandy article together just for you.

Trust us; once you’re done, you’ll not only know what range estimation is, you’ll know how to find it—at least using Mil-dots.

Range Estimation

Range estimation is pretty much what it sounds like.  It’s an estimated distance between you and the target. There are several techniques to estimating range, such as the 100-meter-unit-of-measure method, appearance-of-object method, bracketing method, range card method, and of course, a combination method.

However, for the purpose of this article, we’re going to stick strictly to the use of Mil-dots.

But, before we begin to cover how to estimate range using this method, it’s important to know the various types of problems you may encounter, especially if you were using one of the methods requiring a lot of guestimation. These problems can throw off your calculations and, in turn, you’re round placement.

Nature of Target

The nature of the target refers to its appearance, meaning its outline, contrast, and exposure. We will start with the outline first. Pretend you’re attempting to estimate the distance you are from a deer, and you see a regular outline; that deer will seem closer than a deer with an irregular outline, who’s standing in front of a bunch of bushes or trees instead of being out in an open field.

The outline of your target can give you different illusions as to how far your target is.

It’s like those dumb puzzles your friends keep tagging you in on Facebook. "Only 5% can get this answer right. How many blocks do you see?" When you look at the picture from one angle, you might see 3 blocks, but wait, you tilt your head a little, and now there are 4! Or the famous, "Which line is taller?" Let us help you; IT’S AN ILLUSION! THEY’RE ALL THE SAME SIZE!!!

This same thing could happen to you during range estimation, so beware of the outline.

Next, you have to worry about contrast. If the target you’re looking at contrasts with its background, it’s going to appear closer than it actually is. And just the opposite, if a target is partially exposed to you, it’s going to seem further away than it actually is.

Nature of Terrain

Just as the nature of your target affects appearance, so does the nature of your terrain. For instance, does your terrain appear more contoured because that will make your target seem further away from you. Whereas, if you’re looking over smooth terrain your target will seem closer.

Then, of course, you have to worry about hills. If you’re looking uphill, the target will seem closer, and if you’re looking downhill, the target will seem further.

Light Conditions

Finally, you have to consider light conditions when estimating range distance. If the sun is behind you, the target will seem closer, but it will appear further away if the sun is behind the target.

Former Army Delta Operator Talks Range Estimation

Range estimation has become a lot easier for the average shooter to accomplish thanks to technology. Many scopes and other optics include some type of range estimation reticle built in. Back in the day, Marine Corps Scout Snipers would MIL their targets using the mil-dot reticle built into the 10-power Unertl scopes.

The current rifle scope that the Marine Corps Scout Snipers are using is the Nightforce ATACR 5-25×56 F1.

What if that fancy spotting scope or other optics you use to estimate range goes down, gets damaged, or the batteries go dead? Now, what do you do?

The following video provides you with a solid backup plan. Former Army Delta Operator John McPhee shows how to judge the distance to your target (out to 600 yards) using only your own two eyes.

Laser Rangefinders

Once you get over all the uncontrollable environmental factors affecting the visual estimation of your target, you may decide it’s best to just go ahead and purchase one of those fancy laser rangefinders. Laser rangefinders are great. They can be very accurate, but unfortunately, they don’t teach you the basic skills of milling your target, which can come in handy because technology always fails, eventually, and usually when you need it most.

It’s like learning how to drive a stick shift. If you don’t learn that first, it makes it harder to go back and learn it later. You get lazy, and you get comfortable, but when you need the skill, you won’t have it. And that could be a problem if you don’t have any other option—I guess you’ll be walking. Or, in the case of milling your target, I guess you won’t be getting that headshot.

There are actually a couple reasons you don’t want to rely solely on a laser rangefinder or GPS system—the first being the most obvious, which we’ve pointed out, technology breaks. But, also, they might not always be available to you. Finally, you can’t be certain they’re accurate, especially if you’re on some crazy terrain. Yes, if you’re on a flat surface with no objects to get in the way, a laser or GPS system might give you a perfect reading. But, the chances of a perfect environment aren’t likely, especially if you aren’t on a professionally manmade range.

Range reticles, however, are more reliable because you don’t have to worry about them giving out when you need them most. Of course, if you’re a novice, it may take you longer, and you might not be as accurate, but that’s why it’s important to practice.

What’s a mil dot?

For those of you not taking the easy way out, you might want to know what a Mil-dot is. A Mil-dot is usually found inside your rifle scope or set of binoculars. If you’re looking down a standard crosshair reticle, you might see four small .25 mil dots along those crosshairs. Each of those dots represents 36" or 1 yard if you’re 1000 yards away from your target. If you’re 100 yards away from your target, it equals 3.6".

So, what’s range estimation have to do with Mil-dots, or more importantly, how do we estimate the range between the target and us? Don’t worry; it’s actually not that hard. Yes, there is a little math involved—don’t worry, it’s not too difficult—we’ll cover it below.

Reading your Reticle

If you’re the novice we’re speaking of, becoming an expert at range estimation via a ranging reticle isn’t impossible, but it really does take a lot of practice. It might take an expert 10-second to determine how far away the target is from start to finish. This includes getting steady and plugging in the formula. If you aren’t an expert, it could take much longer. The average time is about 10-30 seconds but could take up to a minute, depending on the environment you’re in. This is why it’s so important to practice. It may not seem like it, but 30 seconds is too much time, especially if you’re faced with an adversary. You better hope you’re quicker and more accurate than he is.

Before we get much further, it’s important to know; that not all reticles are the same. For the purpose of this article, we’re going to stick with the Mil-dot. However, some are mil scaled, without the dot. Therefore, it’s important to know your reticle and how to read it. Sometimes, the reticles will look different, but they act the same. However, things may look a little wonky in some cases compared to what we’re talking about here. This is why it’s important to look up your reticle’s scale and how to read it properly.

What is the equation for milling a target?

Finally, we can get to the fun stuff. How to actually use the Mil-dots method. If you want to calculate how far you are from your target, you’ll first need to know the dimensions of your target—this is why it’s important to get out there and track your data before it’s time to make the shot. Of course, you can always use Mil-dots or MOA to find your target’s size, but that takes time you might not have while in the field. Either way, once you know the target’s size, there are a few ways to calculate the distance, depending on how you want to read your measurements.

You can work your Mil-relations formula to give you a distance in yards like you see below or in meters. The only difference is, you’ll plug in 25.4 instead of 27.77.

Once you’ve plugged in the information, you can easily work the formula and find the distance from you to the target without a fancy rangefinder. It’s that simple.

Error of Probability

Despite how simple the formula is, there’s still a lot of room for error. Let’s say you’re an expert at this stuff—you’re probably not reading this article, but that’s cool—you might be able to get down to 1 mil. Meaning, you can estimate out to about 700 yards without a problem. But, if you’re a novice, you might only be able to get within .25 mils, meaning your accuracy becomes seriously flawed for anything beyond 500 yards.

Your error of probability is how much you’re off on your mill reading. Let’s say you’re looking at a target 40" high. If looking through your scope and you’re off by .1 mil, then your error of probability is .1 mil. In most cases, if your error of probability is .1 mil, then you’re probably an expert. However, we aren’t all experts, and a novice may be more likely to have an error of probability at .25 mils.

Ranging Error of Probability

What’s it look like if you aren’t very accurate? For starters, and this could probably go without saying—but we’re going to say it anyway—your ranging error of probability goes up the further away you are from your target. The lower your skill level is, the higher your ranging error probability is as well. It’s like being new at anything. The less experience you have, the greater the chances are of you sucking at it.

You might be asking, what happens if I’m off by .1 or .25 mils? While .1 and .25 may not seem far off, down range, it will make a huge difference. In fact, the further your target is, the further off you’ll be from the target. Let’s say you’re that .1 mil off shooter. If you’re 500m away from your 40" target, you have a ranging error of probability of .24m—we’ll cover what this means in more detail below.

Danger space

If you’re still sitting at 500m and your target is 40" high, about the size of the average man’s torso, then you’ll have a danger zone of 77m. These 77m means you have that distance before you’ll start to see some real problems, meaning you’re missing your target.

Now, let’s put it all together. At 500m, shooting at a 40" target, a person who’s off by .1mil will have a danger space of 77m. Since your error of probability is only .1mil, then your ranging error of probability is only 24m. Since .24m is less than 77m, you shouldn’t have a problem.

But, what happens if you’re not the expert shooter, but you have the same target at the same distance. Let’s say your error of probability is .25. Again, this may not seem like a lot until you get further away. At 500m, a novice shooter would have a danger space of 77m as well; only they’ll have a ranging error of probability of 56m. That’s more than double the error you’d see an expert shooting. But, even with this error, the novice shooter is still safe because it falls under the danger space of 77m.

However, what happens when you move that same target out to 700m? Well, it’s further away, so your danger space decreases, and your ranging error of probability increases. If you’re off by .1 mill, your ranging error of probability would be 44m, and your danger space has decreased to 48m. As you can see, 44m isn’t far off from 48m, meaning being off by .1m is about all the room for error you have. If you’re off by .25m at that same distance, your ranging error of probability is 102m with a danger space of 48m, which means you missed the target.

Again, the further out you are from your target, and the less experience you have, the harder it is going to be to hit your target because your room for error decreases.

Range Estimation Limitations

Let’s talk about limitations. We’ve already told you why it’s important that the mil-dot system be your primary source for range estimation as far as tools go. But, that doesn’t mean it won’t come with its share of limitations.

Must know target dimensions

Knowing the dimensions of your target is a must. I mean, it is part of the formula, so if you don’t know your target’s dimensions, you might have a hard time with accuracy. Of course, you could always guess, but unless you’re really good at it, it’s not the ideal thing to do. Again, this is where we tell you, practice, practice, practice. You want to find out the dimensions or approximate dimensions of your targets before you’re in a real situation.

We say ‘approximate’ because no target—unless it’s manmade—will be identical. Yes, the average man is xx inches tall, but that’s average. Yes, the average buck is xx inches tall, but that’s the average buck. For every average, there’s that exact same target that falls outside of that range, either being shorter or taller. Skinnier or a little more on the plump side.

So, what do we do to counteract this? We practice by finding the dimensions of any target you would plan on shooting at from a far distance. Once you know this, you will be able to easily plug it into your formula and get the job done that much quicker.

The object must be visible and perpendicular to you

It’s pretty obvious the object or your target must be visible. That’s just part of standard weapon’s safety; if you can’t see your target, then who knows what you’re actually shooting at. Of course, it can also throw off your measurement, which is the main point in reference to ranging your target with a reticle.

But what about the perpendicular part? Why is it necessary that your target be perpendicular to you? Because if the object isn’t perpendicular to you, there’s going to be a tilt, and the object will seem smaller than it actually is. Because of this tilt, you’re going to have to do more math—trigonometry style math—to account for the angle, and why make things harder on yourself than they have to be?

Need an extremely steady position

For those of you who haven’t done this, we’re going to give you another example. Have you ever played a video game as a first-person shooter? If you’re the sniper when you look through your scope, what happens? You can’t seem to get the crosshairs on target, and you see this figure-eight pattern. If you were running first and got your heart rate up, it moves even more. And the further away you are from your target, yes, you guessed it, the more movement you have when you look down your scope.

Unfortunately, this happens in real life too. And trying to find your distance from the target without a steady position is that much harder when you’re using a mil scale, especially one without the dots. The more you shake, the more movement you get, and the harder it is to get accurate measurements.

This is why it’s important to get as steady as possible. Just your breathing alone can cause a lot of movement; now, factor in wind and body position. You need to make sure you’re eliminating as much movement as possible. No, you can’t stop the wind, but you can position yourself, so you don’t shake as much. You can use techniques to slow your heart rate down. Every little bit counts when it comes to steadying yourself and making an accurate shot.

The Importance of Range Estimation

Now that we’ve covered all that, what’s range estimation have to do with anything? Maybe this is something you’re asking yourself right now—or maybe not—but it is important to know, so, like all things worth knowing, we’ll cover it.

Short answer: it’s important to know so you can estimate for bullet drop. The further away you are from your target, the more your bullet will drop. Of course, the environmental factors—which we wrote about in detail here— play their role. But, ballistics also play a part.

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