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Minutes of Angle (MOA), Milliradians, and Mil Dots

Minutes of Angle:

A Minute of Angle (MOA) is simply an accurate way to measure angles.

Minutes of Angle correlate fairly well with the Imperial measurements.

This is because at 100y, 1 MOA is equal to 1.047” and at 1000y, 1 MOA is equal to 10.47”.

As such many shooters “round” 1 MOA down to 1”. This is usually referred to as Inches Per Hundred Yards (IPHY).

Although this makes it easier to translate between inches and MOA, it isn’t exact and so it can cause error when shooting long range if you don’t account for the difference between IPHY and true MOA.

The big takeaway here is that MOA and Imperial measurements ARE NOT the same!

We “understand” linear measurements and so we try to reference the angular measurements to them…but they aren’t the same thing.

Milliradians:

A Milliradian, usually referred to as a Mil or MRAD by shooters, is (just like MOA) simply an accurate form of measuring angles.

Milliradians correlate well to the metric system (meters, centimeters etc.). In fact they correlate better with Mils than inches do to MOA.

For example, at 100m, 1 Mil = 10 centimeters (cm) and .1 Mil (1 Click) = 1 centimeter (cm) and at 1000m 1 Mil = 1 meter and .1 Mil (1 Click) = 10 centimeters (cm).

Notice that no “rounding” takes place.

BUT…just like Imperial measurements and MOA, Milliradians and Metric measurements ARE NOT the same!

Reticles:

Although there are many rifle scopes and reticles available for shooters, the most common type employed by Military/Law Enforcement shooters is often referred to as a Mildot scope or MRAD scope.

A traditional Mildot scope has a reticle that has a series of dots along both the horizontal and vertical planes, with each dot equating to 1 Milliradian.

Traditionally, the adjustments on these scopes were usually made in Minutes of Angle (MOA) as they offered a (slightly) finer adjustment than mil adjustment scopes.

This is why most scopes used for Military and Law Enforcement applications consisted of a Milliradian reticule with MOA adjustments.

However, this meant doing a whole lot of conversions (for example from Mils to MOA) that required a good grasp of mathematics or a calculator. As you can appreciate, it is not something you want to be messing around with under field conditions.

So…before long, (most) Military and Law Enforcement agencies ditched the “mix and match” scopes and adopted true MRAD scopes (Mil Reticle and Mil Turrets).

They then trained their personnel to work in meters, centimeters, and millimeters.

In addition, the reticles changed.

The dots were replaced with short and long dashes. The long dashes represented 1 Mil increments while the small dashes usually indicate .2 or .5 Mil (depending on the type/make/model).

This makes it easier to accurately “mil” targets to ascertain target size or range to target.

Once the benefits of keeping the reticle and the turrets the same became apparent, scope manufacturers began to produce scopes with MOA reticles and MOA adjustments to accommodate the MANY who didn’t want to change to the MRAD system.

A true MOA scope that has a MOA reticle combined with MOA adjustments are every bit as useful as MRAD scope for measuring objects, range estimation, and shooting holds.

The only difference is that the formulas are different.

MRAD vs. MOA:

Deciding which system is right for you isn’t particularly difficult...

If you are most comfortable working in yards and inches, use a MOA scope.

If you are more comfortable working in meters and centimeters, use a MRAD scope.

There are exceptions to this rule but unless there is a good reason to change, stick with what you know.

We understand linear measurements and so we try to reference the angular measurements to them…but they aren’t the same thing.

Military Use:

The MODERN basic Military/Law Enforcement sniper package now consists of a MRAD scope affixed to a .308 or 7.62mm bolt action rifle.

Yes there are other calibres employed as sniper rifles, such as the .300 Win Mag, .338 Lapua Magnum or the .50 cal, but the package which has proven itself time and time again in combat is the basic package outlined above.

It is the package that is used at sniper school, where trainees first learn the art of sniping.

So…basically, there are 3 common setups in use today…

•MRAD

•MOA

•MRAD / MOA (“Mix and Match”)

Despite the fact that many people have moved to either true MRAD scopes or true MOA scopes, there are folks who still use the “mixed turret” system (Mil reticle / MOA adjustments).

So…throughout this book, I will try to give examples for ALL options to keep everybody happy! : )

Confused Yet?

By now, many inexperienced shooters are feeling a little overwhelmed.

I know I was when I first started out!

But you know what…you’ll understand it all soon enough.

I’ll try and break it all down for you so you can understand it all.

Minute of Angle (MOA):

•There are 360 degrees in a circle.

•Each degree consists of 60 minutes.

•So…there are 21,600 MOA in a circle

•1 MOA = 1.047” at 100y (not 1”) and 10.47” at 1000y.

Milliradians (MRAD / Mils):

•There are 6283 mils in a circle (N.A.T.O rounds to 6400 for navigation purposes).

•Each Mil can be broken down into 10ths, i.e. .1 Mil, .2 Mil, and so on.

•1 Mil = 10cm at 100m and 1 Meter at 1000m.

Now for the “mix and match” folks…

•There are 3.44 MOA in 1 Mil.

•3.44 (MOA) x 1.047 (Inches) = 3.6.

•So…there are 3.6” in a Mil at 100y and 36” in a Mil at 1000y.

Now…because you will need to convert what you see in the reticle (Mils) to an adjustment in MOA for your turrets, the most important point to remember is this:

3.44 MOA = 1Mil

This will be important when doing conversions between Mils and MOA…the downside of having a “mix and match” system and why the Military moved on.

While we are discussing scopes…

Something else to be aware of with regards to the scope you are using is whether or not the reticle is in the first focal plane (FFP) or the second (SFP).

With a FFP scope, the reticle size changes with the magnification. This means that if using your reticle, 1 Mil (or 1 MOA) at 500y/m is still 1 Mil (or 1 MOA) not matter what the magnification is set to.

With a SFP scope on the other hand, the reticle appears the same size despite magnification changes. This means that if you are using your reticle, 1Mil (or 1 MOA) at 500y/m will NOT be the same at all magnifications.

This creates a problem when using a SFP scope for ranging objects using the reticle because it can ONLY be done at the scopes “true” magnification.

If you are ranging with your reticle at anything other than the scopes “true” magnification setting, your measurements will be incorrect and you will miss the target.

So…if using a SFP scope, you need to know the “true” magnification setting (usually found in the manual) AND ensure that you are at that setting when using the ranging exercises covered later in this book.

FYI…this also applies to leads when shooting moving targets. If you ascertain your leads at a certain magnification setting, they will only work at that magnification setting.