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User Guide for Mil-Dot Equiped Optics
This guide is intended to provide the user of a Mil-Dot equipped optic with information on what the reticle is used for, the basics of its use and how to train yourself to better employ and realize the full potential of this reticle. DISCLAIMERTHE INTENT OF THIS DOCUMENT IS TO PROVIDE SOME INFORMATION TO ENABLE USERS OF MIL DOT EQUIPPED OPTICS TO DEVELOP SKILL IN THEIR EMPLOYMENT. THE ACTUAL USE OF THIS INFORMATION IS THE RESPONSIBILITY OF THE USER. MISUSE OF THIS INFORMATION COULD RESULT IN LEGAL RAMIFICATIONS. TREAT ALL WEAPONS AS IF THEY ARE LOADED, ALWAYS ASSUME THIS AND BE DEADLY SERIOUS ABOUT IT. NEVER USE UNSUSPECTING OR UNAWARE INDIVIDUALS AS MIL PRACTICE OBJECTS. THIS DOCUMENT IS NOT ALL INCLUSIVE; IT TAKES PATIENCE AND PRACTICE TO BECOME SKILLED AT ALL SHOOTING ASPECTS. NO AMOUNT OF MONEY OR DEVICE IS FOOL PROOF MEANING THAT YOU CANNOT BUY SKILL. USERS SHOULD PRACTICE ANY AND ALL TECHNIQUES POSSIBLE TO DEVELOP APPLICABLE METHODS. PREFACEWe want to give our sincere thanks to Michael Haugen for his help in preparing this Mil-Dot Guide. Over the years a common question has been where can I find information on the mil-dot and it's use?. Mike spent countless hours writing this guide. When we asked him for some professional guidance he did not hesitate to offer his time. Many of you may know Mike but for those of you who do not here is his bio. Michael Haugen is currently an active duty US Army Special Forces Warrant Officer with 24+ years of service. He has an extensive background in conventional and special operations snipers and sniping and has taught a great many US and foreign snipers. His background facilitated his contribution for this document and writing for Guns and Weapons for Law Enforcement, Police and Security News, and the now defunct Tactical Shooter magazine. He currently resides with his wife and 2 children in Olympia Washington. ©Michael Haugen 2002. All or parts of this guide may not be reproduced without the express written permission of the author. Congratulations on your recent purchase or interest in the use of an optical product that features the mil-dot reticle. Lets begin by issuing a disclaimer; some of you out there may find some controversial information contained in this manual, however this information has been verified and tested by a variety of professional sources. Whether you are a beginner or a seasoned user of mil-dot equipped optics, you will find something useful contained in this document. There are two basic reasons that people purchase optics with this reticle, to estimate range and/or to hold off for winds. The problem with this reticle is that it requires a little training and some practice. Having said this, however, this reticle is extremely versatile and useful and when properly used will allow the shooter to accurately engage and hit targets at ranges previously thought impossible. In the beginning, new shooters will doubt the accuracy of this system because ranges they previously thought were distant equate through the math to be much closer. This is very typical because most shooters way over estimate range. How many times have you heard I took that animal at 500 yards when in reality it was probably under 200 (many times under 100). As time goes on with more practice you will notice that your ability to estimate range by eye will dramatically increase which in turn will serve as a check against your milling allowing to quickly estimate the range and engage the target. WHERE DID MIL DOTS COME FROM AND WHY ARE THEY USED? Earlier in the 20th century, the U.S. Infantry used Mils (see specifications for definition and value) to correct the trajectory for indirect fire and crew served weapons. This was done mainly because Mils are a finer measurement than degrees and enabled them to be more accurate. The Infantry divided a circle into 6280 parts or 1/6280 th = 1 mil. This was a slight deviation from the truth but was close enough and made it easier for them to compute and work with. Shortly thereafter the Artillery took notice of the system and decided to refine this system even further (due to their requirement for more precision fire) and rounded the number to an even easier number, 6400 mils to a circle or 1/6400 = 1 mil or 17.8 mils = 1 degree. This system stands today and is widely used in all services. However, this is not the mathematically correct system utilized in a Mil-Dot reticle which uses 6283 parts of a circle. The USMC was the first U.S. military service to in corporate a mil dot reticle in sniper optics by having it installed by J. Unertl for use on the M40 sniper weapons system in 1979. When the Army decided to incorporate a range estimation tool into it sniper optics it chose this system and had Leupold make the reticle accordingly. I should clarify this point for those out there not familiar with the Leupold M3A Ultra currently used by the US Army. Many people believe that the Mark IV M3 that they see advertised by various retailers is the same as the optics on the Army M24. Although they are identical in appearance, they are not the same. Specifically the reticles are different; the M3 Ultra uses an etched glass reticle with round or Army mil-dots , whereas the available Mark IV M3s sport a wire reticle with the USMC oblong dots . Since the U.S. military adopted mil dots for use by its snipers, this reticle pattern has become a favorite of law enforcement, varmint shooters and hunters. The popularity of the mil dots has resulted in them being offered by virtually every optic manufacturer today. Around 1990 the mil-dot was first installed in variable power scopes. Most of these scopes had second focal plane reticles, meaning the scope was to be set at a specific power. For example, variables up to14X would have 1 mil spacing at a maximum power setting. On some higher power variables the scope could have a mil-dot installed but would usually have 1 mil spacing at approximately 10X. Some optics offer first focal plane reticles. The advantage is allowing 1 mil spacing regardless of the power setting. You should know whether you have a first or second focal plane reticle so you are aware of the correct power setting giving 1 mil spacing. This interest has also resulted in numerous variations being developed by several companies at the request of users. Most of these variations come in the form of dot spacing and number of dots presented. The most exciting news in the mil dot reticle world is the recent development of the GEN 2 Mil-Dot reticle offered by Premier Reticles which dramatically increases the versatility of the reticle. This GEN 2 reticle is now offered in the first focal plane of Leupold 3.5X10 scopes and a 12X-40X 60mm Leupold spotting scope. Also available in second focal plane 4X-12X, 6X18, 4.5X-14X, 6.5X20 and 8.5X-25X at approximately 10X. The power ring is marked to show exact position for 1 mil spacing. Mark 4 M1 , M3 10X and Mark 4 16X GEN 2 reticles are available. Regardless of which version of reticle you have purchased, I HIGHLY encourage you to read this manual and PRACTICE, PRACTICE and PRACTICE and you will have a system that is time and combat proven to deliver reliable and consistent hits to maximum effective range of the weapon it is used on. MIL-DOT SPECIFICATIONSThe term or measurement of Mils (or Milliradian) is a trigonometric function used to configure and use the Mil-dot in estimating range. Here are the specifications. 1 Milliradian = 1/1000 th of a radian, 1 radian = 2 PI 1 Milliradian = .0573 degrees or 6283 parts of a circle Since I have gotten to this point let me cut to the chase and present you with the math that accompanies what I have already said.
360 degrees = 1 circle
Therefore: ** Note: 1 Minute of Angle = 1.047 @ 100 yards (True) While we are distinguishing between Army and USMC reticles, I feel it is prudent to mention another difference. Not only are the mils themselves different but the value of the dots is also different. Army dots while commonly called ¾ mil dots are in reality 3/4 MOA dots (or .22 mil). This is to say that one dot subtends (covers) three quarters of a minute of angle or .75 inch at 100 yards. The USMC dots are 1/4 mil dots (or .86 moa) from edge to edge. Each USMC oblong dot subtends .86 at 100 yards. The new Premier GEN 2 Mil-Dot reticle further adds to the mix by presenting a reticle that offers a dot that is .2 mil in diameter (.675 moa) or .675 @ 100 yards. With Army dots, a quarter mil (1/4 mil) is the width of the dot from edge to edge plus the width of the line. As you can see from the diagram the 1/4 mil, ½ mil and 1-mil locations are depicted. The commonly missed identified are the 1/4 mil and the 3/4 mil.
USMC dots, the measurements are easier to identify and remember.
The GEN 2 Mil-Dot reticle has taken this further
You will notice that there are differences in each reticle. None are truly better than the others, however depending on things like previous training and intended use one reticle may appeal to you or be more useful than another. Keep in mind that all of the above do the same things; additionally there are variety of other and custom mil dot reticles available that will give the shooter varying degrees of ability. The point here is you must know and practice with whatever reticle you have. I am sure that all of the above is somewhat confusing but, you have to remember that the mil-dot system merely provides aiming reference points and a range estimation tool. Where the actual locations of the 1/4, 1/2?, 3/4 or 1 mil point are depends on where your starting point is. The GEN 2 Mil-Dot breaks the reticle down in .1 mil increments. What I have drawn above gives you the quick reference points. If you are set on using center - center or edge - edge starting points then you will have to find those subsequent points. The bottom line is two fold. One, know what the values are of the reticle you are using. Two, use the same points all of the time. Do not get wrapped around the axle about what is best (edge to edge or center to center), just pick which ever one is easiest for you to use. One of the problems is that all of the reference material available today does not make the distinction between the two reticles and assumes the reader knows which system he has (and that there is a difference). The US Army manuals, TC 23-14, FM 23-10, and ST 31-20-4 all use the round dots, while the USMC manual FMFM 1-3B uses the oval dots. Civilian reference like John Plaster's Ultimate Sniper which plagiarizes several manuals use the Army dots as the example but use USMC math. Additionally, optic manufacturers do not always tell you how to use their reticle. I am sure that most of you have skipped right to this page, as you want to jump ahead and get to using the optic. I have to HIGHLY recommend that you at least look at the diagrams and values associated with the reticle patterns listed under specifications. All right then, lets get to it. The vast majority of users will employ the optic primarily to estimate range, some will also use it to hold for wind and some will use it to calculate and hold leads on moving targets. I will address the latter two uses further into this instruction. There are two components to range estimation; the mechanics and the math. The mechanics encompass the physical methods of placing the reticle on the target and the reticle. The math is taking the mils read and converting it to a usable range. THE MECHANICS This is definitely the hardest part of range estimation using the mil dot reticle. It requires the shooter/user to place the reticle on the target (of known size), hold it long enough to accurately read it (depending how accurate you are trying to be to the nearest .1 mil). Whenever the majority of people think of a reticle on a target they envision the center of the cross hair placed on the desired point of impact (POI). In order to use a mil dot reticle to estimate range the shooter/user can use a variety of methods, all of which produce the same results. The main differences in the methods are what the shooter/user is most comfortable with and what the target is exposing. The MOST important aspect of using the mil dot reticle for range estimation is a STEADY HOLD on the target. As you use the reticle, you will realize just how hard it really is to hold the reticle on the target. Most shooters will tend to move the reticle in the direction that they are reading, however many shooters will do the opposite. The shooter must practice shooting positions to determine what is best. All but the best shooters are able to hold a rifle/optic steady enough without a rest or support to accurately read the reticle. Shooters should ALWAYS seek to use some form of rest, bipod, sling etc. to develop a STABLE , DURABLE , and SUSTAINABLE shooting platform. When attempting to estimate range of living (for now) objects, they never stay in one place very long so; it is imperative that the shooter be practiced and be able to read the scale quickly and accurately. In order to develop this skill the shooter must practice, practice and practice ( we will cover practice techniques later ) using the reticle against targets at different ranges and of different sizes. Additionally the shooter should try all of the methods to determine which he/she prefers and the advantages/disadvantages of each.
READING THE RETICLE. In order to use the reticle you must be able to read it. As mentioned elsewhere in this manual you must be able to read the reticle to the nearest .1 mil. Please refer to the diagrams depicted in SPECIFICATIONS for a break down of the specific reticles. Here is a generic break down of a mil dot reticle: The picture is not to scale but provided to illuminate the discussion. Notice that what is depicted is not to the nearest .1 mil. To do so to scale the drawing would be too crowded to be useful. As depicted the .25, .5 and .75 mil are usually easy to find, the user must find the .3, .4, .6, etc locations. Keep in mind that although there is not an exact point annotated on the reticle, it behooves the shooter to learn to guesstimate where these points on the reticle are to lessen the range estimation error. Regardless of which method you are going to use, you MUST know the target size (you will see this again). For the sake of this document, we will use the following;
You will notice that Gordy the Ground Hog is 10 inches tall when he stands, which in your world is the average ground hog height. Once you have the target size you have to decide on which method to use in order to obtain a mil reading. Here are some of the more popular methods: CROSS HAIR METHOD. As the name applies, this method uses the center of the cross hair placed at a point on the target then the reticle is read up, down, left or right. Keep in mind that the cross hair can be placed on any point and the target and mils read from there. This is the most widely used method because it is the most natural, placing the cross hairs on the target.
HEAVY POST METHOD. Similar to the cross hair method, the heavy post located on any of the four sides (top, bottom, left and right) is placed onto a base line and then mils read from there. The benefit of this method is that the heavy post is easier for most people to hold on a distant target (especially older shooters).
MIL DOT METHOD. Again, like the other two methods, a distinct aiming point is placed on the target and mils read from there. In this case, a dot is used verses the cross hair or a heavy post. This method is favored by some because the dots are easy to place on the target and for some easier to hold. One thing to keep in mind is that you are already into the mil scale when you place the reticle on the target and you must factor this into your calculations. Again remember, you MUST begin reading at the BASE DOT or factor its value is you begin elsewhere (i.e. if you begin reading from the top of the post as depicted above the reading would be 3.4 mils verses if you begin at the base dot which would be 2.4 mil and would be CORRECT).
There are two ways that you can derive range using a mil dot equipped optic, to manually compute it either by long hand or by using an electronic calculator OR to use one of several shooter aids that are on the market. The most notable shooter aid available is the Mil Dot Master â ; a slide rule type device, which provides the shooter with the ability to line up mils read with the target size in inches and gives you the range to the target. The other device is what is termed a cheat sheet and resembles a spreadsheet depicting mils read on normally the left side and target sizes across the top. By intersecting the two, you arrive at the range to the target. While these devices are definitely handy, anyone using this reticle should know the math associated with it so that when they forget the device or cheat sheet they can still use the reticle to its maximum ability. Therefore, we will begin with the math (long way) of doing this. CALCULATIONS Using a mil dot reticle is a mathematical proposition requiring some calculating in order to arrive at a solution. For range estimation problems there are three components; target size (Tz), mils read (m) and range (R). You MUST have two of the three to arrive at the third component. Most commonly, the shooter will know the target size and by using the reticle will arrive at mils read, here are the formulas:
In short:
I am sure you notice that target size is required in yards or meters. Most of the time you know your target in inches (varmints), therefore the below formulas will help you convert and arrive at a usable range. The first formula for each is the easiest but not the most precise. Try them all out and decide for yourself what is best; For Meters: Object size (in) divided by 39 x 1000 divided by mils read Object size (in) x 25.4 divided by mils read For Yards: Object size (in) divided by 36 x 1000 divided by mils read Object size (in) x 27.77 divided by mils read Lets try this out; You are a varmint hunter and looking down range you see a fat ground hog that happens to stand up looking around. You think he is 10 inches tall and place your reticle on him. You mil Mr. Ground hog at .6 mils, plugging what you now have into the formula this is the result; 10 inches divided by 36 x 1000 divided by .6 equals 462 yards OR 10 inches x 27.77 divided by .6 equals 462 yards OR 10 inches divided by 39 x 1000 divided by .6 equals 427 meters OR 10 inches x 25.4 divided by .6 equals 423 meters Shooter AidsAs mentioned above, you can also enlist the help of a shooter aid such as the Mil Dot Master â (MDM) that will take the math out of this effort and provide you with an quick firing solution. The MDM is easy to use and will offer the shooter with more options than most will ever need (such as slant range corrections). For those interested in the MDM, I encourage you to visit their web site at http://www.mildot.com/ where you can use a virtual example. One last word on the MDM, you MUST read the instructions and understand them for it to work, it is NOT magic and will not do all the work for you.
Another form of shooter aide is what is termed a cheat sheet. This is a spreadsheet like form that shows mils read on one side and target size across the top. This is a simplified version of the MDM but does not require any sliding or moving of anything. Down side is that it only does one thing, provide range from target size and mils read. I will provide a larger version of this diagram at the end of this manual.
So you can see Mr. Ground Hog is about to have some problems if you can also call the wind and hold the target which brings us to the next subject, using the reticle to hold for wind. HOW TO TRAIN AT RANGE ESTIMATION. Here are some pointers for increasing your range estimation skill.
Routine exercises as above will develop your ability to accurately and quickly estimate the range to any target. WIND HOLD OFFSHolding off for wind although simple sounding is an extremely difficult proposition and next to range estimation the most difficult of all shooter SKILLS to master. We could devote pages to this issue and describe a variety of methods to determine wind, however this manual is about mils not wind calling. We cannot however talk about using mils to hold off winds without at least discussing winds a little. There are three components to calling wind, identifying the wind velocity in mph, identifying wind direction, and identifying wind value in minutes of angle or mils. There are several ways to accomplish these three things; WIND VELOCITY: Wind velocity is normally expressed in miles per hour (mph) or perhaps kilometers per hour (kph). Either way wind has a speed that must be identified/recognized. There are two ways to determine wind; use of an instrument to measure it or by visual indicators. The next aspect is where to measure/read the wind; at the shooters position, mid range or at the target. Without getting too deep into this issue I will share how I do it and you can make up your own mind. I use visual indicators (mirage and vegetation) to identify the wind velocity and direction. I do this because I am a tactical shooter and cannot afford to use an instrument at my position without compromising it. I look at the wind at mid range and at the target because this is where the bullet is under the most contact with the wind. There are other sources that can give you what the value of mirage or waving vegetation is, therefore I will not go into it here suffice to say that like the rest of this issue PRACTICE, PRACTICE, PRACTICE are the keys to being able to identify and call the wind. Once you have determined the wind speed and direction, you can give it a value in MOA or Mils. Most experienced shooters SWAG the wind and shoot, what they feel is right. By doing, this they develop experience in what a given wind is worth in mils or minutes. If you determine the wind in moa you must convert it to mils then hold that IN THE DIRECTION OF THE WIND . Of course, it is much easier to determine the wind in mils thus eliminating the need to convert. Wind in mils will normally be in quarters (1/4, ½, ¾, etc) keeping in mind that one-mil equals 3.438 moa. Lets recap; if you are looking down range at a target located 300 yards from you and you determine there to be an 8 mph left to right wind present at the target. Consulting a handy wind chart you see that the wind is worth 2 moa. In order to figure out the mil hold off you have to determine what 2 moa is equates to in mils. Since there is 3.438 moa in a mil, 2 moa is 59% of a mil or just over a ½ mil hold TO THE LEFT. That is you place the center of the reticle ½ mil to the left of the target to compensate for the wind. TRAINING ON CALLING WIND . Like everything else, this requires practice, practice and more practice. Unlike range estimation, wind calling will require you to also shoot to confirm or deny your call. One way to gain experience is to attend competitions even as an observer and watch experienced shooter deal with the wind. There you can see calls (you will have to make some friends there first) and the results on the target. I should mention the use of so-called Kentucky windage, which is usually firing multiple rounds until a hit is obtained. This may be applicable for some of you. In order to develop a skill at calling wind, you must start using known wind, for this an anemometer (wind meter) is needed. Look at the wind, make a guess and then measure it. Over time, your skill will increase to the point that you will become accurate. MOVING TARGETSSome of you will use the mil dot reticle to engage moving targets. This is an extremely difficult task not to mention hard to practice. Professional shooters will use known distance ranges with moving targets to practice this skill. There are three levels of movers; walkers, fast walk or slow run (trot) and run. You notice that I have not listed dead sprint or fast run, this is because engaging targets at these speeds is beyond the scope of most shooters and should not be attempted unless you are extremely skilled. Of the three speeds, you can of course further sub-divide them but you only make it harder to identify. Like wind, you must be able to determine target speed from which you can determine a lead. A lead will be determined by not only target speed but also range to the target and caliber being used. You can mathematically calculate a lead by using a good ballistics program like that offered (for free) by Serria Bullets to determine the Time Of Flight of a given projectile/caliber for a given distance. You might want to take a look at the delivered energy at that range to see where your limits should be with reference to the ability to drop the target. Once you have the TOF and range you then factor in rifle lock time and target speed to arrive at a lead.
The math that is involved here is pretty simple, but requires a little computing. Say we are looking at a walking Deer. Lets say that the deer moves at 2 mph; seeing that 5280 feet are in 1 mile, therefore there are 10560 feet in 2 miles, divide this by 60 (60 minutes in an hour) and we arrive at 176 feet in a minute, divided by 60 (60 seconds in a minute) and we arrive at 2.93 feet per second. We are shooting a .308 Winchester from 300 yards using 168 grain Match King (I know it is not a preferred hunting bullet) with a muzzle velocity of 2650 feet per second and a TOF of .382677903 seconds (to travel the 300 yards). We are shooting a Remington 700 BDL with a lock time (time it takes the firing pin to hit and ignite the primer) of .003 seconds. Therefore, we add the lock time to the TOF to arrive at a total time from trigger being pulled until the bullet impacts at the target area equals .3856779 seconds (TOF plus lock time). We now have to figure out how far our target will move in the amount of time it takes for the bullet to get there. As we said the deer is moving at a speed of 2.93 fps divided by 12 gives us 35.16 inches per second. Taking this number we multiply the Total Time of Flight (TTOF) to arrive at a distance of 13.5 inches, or better said the deer will move 13.5 inches in the time it takes the bullet to reach him. 13.5 inches equals 4.5 minutes of angle at 300 yards (1 moa @ 300 yards equals 3 inches). With the given 3.375 minutes of angle to one Mil, we now arrive at a hold of 1.3 mils but since 1.3 Mil is not in the reticle, we have to use 1.25 or 1 ¼ Mils. Here it is graphically:
HOW TO TRAIN. As noted in the beginning of this section I noted that this skill is extremely difficult to train. However, if you have the means or devise some way of making a moving target in an area where you can train you should do so at every opportunity. Here are some pointers:
Click here for a fullsize table of mils
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