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Maximizing the Mil Reticle (Shooting Voodoo)

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Shooting Voodoo  Maximizing the Mil Reticle By Ian Kenney  Milliradian based reticles have been utilized in riflescopes since the 1970’s when the US Marine Corps adopted the Unertl 10X sco pe for their M 40A1 sniper rifles. The scopes had a mildot reticle install ed in the scope to a id in ranging a target at an unknown d istance to i ncrease the probability of a first round hit. Today, a mil-based reticle of some sort can be found in the riflescopes of military, law enforcement, and civilian shooters a ll around the world. A mil-based reticle is a mult i-funct ional tool that includes the ability to estimate the range to a target, compensate for the trajectory of the bullet, and speed up the zeroing process.  The Milliradian  First allow me explain what a milliradian is. A mi lliradian is a unit of measure typically used in engineering to derive angles from a circle, which is similar to another unit of angular measure common to most shooters, the minute of angle. The difference betwee n the two howev er is that the mill iradian is a coarse r unit of measure than the minute of angle, meaning one milliradian will exte nd farther than one minute of angle. There has been some debate however as to the exact MOA values of some mil reticles going back to the first mildot reticles used by the US Ar my and USMC. For the purposes of this article, howev er, I will only use the engineering specification of the milliradian since most of the mil-based reticles in use, are based around it. These include reticles from Premier Reticles, Schmidt & Bender, Leupold, Nightforce, and so on. The specifications of a milliradian are: 360° Circle = 6283 Milliradian One Milliradian = 3.6” @ 100 yards One Milliradian = 3.438 MOA One MOA (True) = 1.047” @ 100 yards  Mil-based Reticles and Mil-based Adjustments  Most tactical riflescopes employ a mil-based reticle of some sort and below I’ve included a couple examples of mil-based reticles.  
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Shooting Voodoo

Maximizing the Mil Reticle

By Ian Kenney

 

Milliradian based reticles have been utilized in riflescopes since the 1970’s when the US Marine Corpsadopted the Unertl 10X scope for their M40A1 sniper rifles. The scopes had a mildot reticle installed in thescope to aid in ranging a target at an unknown distance to increase the probability of a first round hit. Today,

a mil-based reticle of some sort can be found in the riflescopes of military, law enforcement, and civilianshooters all around the world. A mil-based reticle is a multi-functional tool that includes the ability to estimatethe range to a target, compensate for the trajectory of the bullet, and speed up the zeroing process.

The Milliradian

First allow me explain what a milliradian is. A milliradian is a unit of measure typically used in engineering toderive angles from a circle, which is similar to another unit of angular measure common to most shooters, the

minute of angle. The difference between the two however is that the milliradian is a coarser unit of measurethan the minute of angle, meaning one milliradian will extend farther than one minute of angle. There hasbeen some debate however as to the exact MOA values of some mil reticles going back to the first mildotreticles used by the US Army and USMC. For the purposes of this article, however, I will only use theengineering specification of the milliradian since most of the mil-based reticles in use, are based around it.These include reticles from Premier Reticles, Schmidt & Bender, Leupold, Nightforce, and so on.

The specifications of a milliradian are:

360° Circle = 6283 MilliradianOne Milliradian = 3.6” @ 100 yardsOne Milliradian = 3.438 MOA

One MOA (True) = 1.047” @ 100 yards

Mil-based Reticles and Mil-based Adjustments

Most tactical riflescopes employ a mil-based reticle of some sort and below I’ve included a couple examples of 

mil-based reticles.

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Mil-based reticles can be found in many of the tactical riflescopes on the market, however the exactdimensions of the mildots, or hash marks, can vary from manufacturer to manufacturer. For example the

Premier Gen II reticle uses a mildot that is .2 mils in diameter while the US Army mildot found in the Leupold

M3A uses a .22 mildot. This is why it is important to learn the subtension of the mil-based reticle you will beusing to mitigate any possible mistakes. Knowing the correct subtension of the reticle will also aid the shooter 

in being able to precisely break the reticle down and accurately judge the distance to the target.

As useful as a standard mildot can be, reticles such as the Nightforce MLR and Premier Gen II offer featuresthat enhance the mil-based reticle, making it easier to use and more versatile. Mil-based reticles like the MLR

and Gen II offer half mil hash marks that make it easier to break up the reticle for easier ranging and moreaccurate trajectory compensation. In addition to half mil hash marks, some reticles offer hash marks at theend of the reticle that break the milliradian down to even finer increments to aid in even more accurate range

estimation.

In addition to mil-based reticles, some manufacturers will also make the elevation and windage adjustments

milliradian as well to match the adjustments to the reticle. The most common click value when talking about

milliradian adjustments is one click being equal to 0.1mrad or one click being equal to .36” @ 100 yards or 1cm @ 100 meters. Therefore ten clicks will equal one mill iradian or 3.6” @100 yards or 10 cm @ 100 meters.

Just like when using MOA, the value of the milliradian increases with distance. At 200 yards one milliradianwill cover 7.2” and at 300 yards it will cover 10.8”, and so on. Matching the reticle and the elevation/windageadjustments has some distinct advantages over scopes that use a mil-based reticle with MOA adjustments.When the adjustments are matched, what the shooter sees in the riflescope as far as a necessary correction

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is simply what needs to be dialed into the scope. Scopes that have 1/4 MOA adjustments will require aconversion in order to get the proper elevation and/or windage adjustment.

Here is a table of conversions:

Conversion MOA to Milliradian Milliradian to MOA

Formula MOA Value ¸ 3.438 = MilValue

Mil Value X 3.438 = MOAValue

Example 7.25 MOA ¸ 3.438 = 2.1 Mil 2.1 X 3.438 = 7.25 MOA

Using the Reticle to Range an Unknown Distance Target

Ranging a target that is an unknown distance away from the shooter is something that mil-based reticles were

designed to do from the start. However, using the reticle for this purpose requires a lot of practice to becometruly proficient and get accurate range estimates for distant targets. In order to effectively use the reticle torange the target, the shooter must know the size of the target he is ranging, in order to complete the

necessary math equation.

When doing range estimation with a mil-based reticle, use the following equations to get a distance to the

target.

For distance in yards: (27.77 X Target Dimension) ÷ Mil Reading = Range

For distance in meters: (25.4 X Target Dimension) ÷ Mil Reading = Range

The first step in getting an accurate range estimate is to get into a steady position, typically a prone position,and align the reticle with the target. When aligning the reticle, place the crosshairs on the 6 o’clock edge of the target or at one of the bottom corners. The thick post of the crosshair can also be used instead of the

crosshairs when getting a mil reading.

The next step is to measure the height and width of the target in mils and plug those figures into one of the

math equations given above. In this case we’ll use the equation for yards.

Height:

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(27.77 X 40”) = 1110.8 ÷ 2 mils = 555 yards

Width:

(27.77 X 20”) = 555.4 ÷ 1 mil = 555 yards

When doing range estimation using a mil-based reticle it is always best to range both the height and width of the target and average the two figures together to get the best estimate possible of the range to the target. Inthis case, both mil readings yielded the same distance so we can figure the target is just past 550 yards and

the appropriate amount of dope needs to be put on the scope.

Here is another example of using the reticle to range a target.

The disc extends to just below the second mildot, since this is a Gen II reticle the dots are .2 mil in diameter,making the mil reading 1.9 mils. Since height was checked first, check the width next to confirm the milreading. Plug the mil reading into the range estimation formula and you will get a range of 146 yards.

Ranging Aids

The above equations can be performed on a calculator, however the easiest way I’ve found to get the range to a target

when using a mil-based reticle is to use a Mildot Master. The Mildot Master is a sliding scale calculator that can help make

fast, accurate range calculations in yards or meters. Additionally the Mildot Master can make adjustments for slope to the

target and it even has an area to affix ballistic information. Mildot Masters can be easily purchased from online retailers

like US Tactical Supply and others who stock data books, slope dopers, and other precision rifle accessories. When you

purchase the Mildot Master though, be sure to thoroughly read the instructions to fully understand the Mildot Master’s

capabilities.

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Another method of fast range estimation without a calculator is a mil relation chart like the one pictured below. A mil

relation chart, or cheat sheet, is a spread sheet that has target sizes along the top and mil readings down the left side. To

use this chart simply find the target size and the mil reading and then trace along until you find the yardage where they

intersect. This method is not perfect since it only provides ranges for the targets and mil readings listed, anything in

between would require some guess work, but it works in a pinch.

Considerations When Ranging

When performing range estimation with the reticle, some environmental factors can make getting accurate

ranges difficult. For example, if it is hot and humid outside, mirage can severely obscure the edge of thetarget making it difficult to get an accurate mil reading since the edges of the target would appear wavy.Another factor that needs to be considered when performing range estimation is the targets relationship to the

shooter. If the target if facing away or down from the shooter, the mil readings will be skewed by the angleand an incorrect range estimate will result. If the target is facing turned at an angle facing away from theshooter it is best to get a mil reading for only the height of the target. If the target is facing downwards or the

shooter is looking down at the target, it is best to range the width of the target since it will be less skewed bythe angle.

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Practice, Practice, Practice

When it comes to ranging an unknown distance target practice is the only way to stay proficient at breakingthe reticle down and performing the calculations in order to get an accurate range estimate. Range estimationusing a mil-based reticle is a perishable skill and one that fewer and fewer people are learning given the

proliferation of laser range finders. While laser rangefinders are excellent tools, they should not be the onlymeans of obtaining a range since batteries die and electronic components can break. One way to practicerange estimation is to range targets that are a known distance away and check your estimate to the actual

distance. Another method is to range an unknown distance object and then check it using a laser rangefinder. However you practice range estimation though, always use safe firearms handling practices and

ensure the weapon is unloaded before you get down behind it or use a spotting scope with a mil-basedreticle.Using a Mil-Based Reticle For Trajectory Compensation

A mil-based reticle can also be used to compensate for the trajectory of a round to make a fast follow up shotor to engage multiple targets at varying distances.

Follow Up Shots/Zeroing:

A mil-based reticle excels at allowing the shooter to make fast and accurate follow up shots should the first

round miss and the splash was observed.

Here the shooter’s

first shot was off target but theshooter observed

the splash 2 milsright and 1 milbelow the desired

point of impact.All the shooter has to do is bringthe reticle up 1 miland left 2 mils and

fire again,impacting dead ontarget. This method works well when a time limit or shifty winds make attempting to dial the correction into the

scope impractical.

In the same way the reticle was used to rapidly engage the target with a follow up shot the same process can

be used to zero the scope by “reading” the reticle. Using the above example, the shooter notices the impact 2mils right and 1 mil low from his desired point of impact. To zero a scope that has milliradian adjustments, allthat is needed to zero the scope is to dial 2 mils left and 1 mil up. Confirm the correction by shooting a groupand the zeroing process is complete. With a scope that has MOA adjustments a conversion will have to beperformed in order to figure out the proper amount of adjustment. This is why it is highly recommended thatthe scope have a matching reticle and adjustment configuration.

Multiple Targets, Multiple Distances:

The mil-based reticle is very effective at engaging multiple targets at varying distances when the scope is setto a mid-range zero and the reticle is used to compensate for targets farther out and closer in than the zero

distance. This technique requires some practice but when a shooter achieves a good level of proficiency, itcan be surprising how fast targets can be engaged.

This technique works best if the drop data is in milliradian. If it is in MOA use the conversion equation to

convert it to Mrad.

The first step is to use a mid-range zero to set the scope too, I like to use a 400 yard zero since 100-600 yards

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is generally no more than 2.0-2.5 mils above and below the crosshairs.

Once a mid-range zero has been chosen, subtract that distance’s mrad value from the other zero values to

determine the hold over or under points on the reticle.

Example:

2.6 mrad - .7 mrad = 1.9 mrad, which would be the hold under point for a 200 yards using a 400 yard zero.

Below are the data card and an example of a mil hold over diagram for M118LR.

I’ve found that this technique works best with the magnification is set to about 8X-10X depending on thedistance to the target and how spread out they are. It also helps if the scope has a first focal plane reticle,

since I can dial the scope to any magnification and the reticle will still be correct. Scopes that have secondfocal plane reticles are normally only correct at the highest magnification and going to a lower power canmake calculating the hold points more challenging.

Wind Holds:

The reticle can also be used to compensate for the effects of wind on the bullet’s trajectory instead of attempting to dial the correction in. This works well in shifty winds or under other time constraints whendialing the wind correction into the scope is impractical. Again, this technique works better if the drop data is

in milliradian since the correction is easily applied to the reticle.

Example:

The target is 400 yards away with roughly a 10 mph wind coming from the left.Look at the data card and see what amount of hold is necessary.

Hold left of the target, since the wind will push the bul let right, and place the 1.0-mil mark on the center massof the target.Using the proper fundamentals of marksmanship the bullet should impact in the center mass of the target. 

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This technique is very effective to the point that many long-range shooters rarely use the windage knob tocorrect for wind since this technique is just as accurate and can react to shifting winds faster.

Of course, the only way for this technique to be truly effective is to get out and practice reading the wind andthen applying that to actual long-range shots. Sometimes it’s helpful to use a personal weather station tohelp confirm wind estimates or see how different wind speeds effect the environment. For instance what a 15mph wind does to tree branches and grass is quite different from what an 8 mph wind would do to the sameobjects. Just like when using the reticle to range with the only way to become really good is to practice,

practice, practice.

Movers:

In much the same way the reticle was used to compensate for wind, the reticle can also be used to engagemoving targets. The amount of lead necessary will depend on the distance of the target, the speed of thetarget, and the time of flight of the bullet.

There are a couple of formulas though that will help calculate the hold required to engage a moving target.

To figure the lead from center mass in feet multiply the time of flight in seconds by the target speed in feet per second

Example:

.7 second TOF X 4 fps = 2.8 feet lead from center mass

To figure out the lead in milliradian use the following formula:

(Lead in feet X 12) – 6 ÷ (Range X .035) = Mil Lead from Leading Edge

Example:

(2.8 ft x 12) – 6 = 27.6; (500 yds X .035) = 17.5; 27.6÷ 17.5 = 1.6 Mil Lead

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Keep in the mind that even though the mathematic formulas give you a lead to use, it doesn’t necessarily

mean that it will be perfect. In reality leading a target requires practice and data collection since a person maylead a target differently for a target moving 4 fps from right to left than they would leading a target going fromleft to right.

In the End

Mil-based reticle are an incredible tool for the long range shooter that can perform a variety of functions thatcan help get rounds from the point of aim to the point of impact. However, as I stated many times above,using mil-based reticles effectively requires a lot practice to gain and maintain proficiency in estimating range

and compensating for the trajectory of the round. Whenever practicing though I want to stress to always usesafe firearms handling practices and ensure the rifle is UNLOADED before you get down behind the rifle.

2010 Shooting Voodoo


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