MIL or MOA? Why? DATA, not a DEBATE!

LoonWulf said:

I've always kind of wondered if there's any reason to even have a graduated reticle when shooting known distance, and with a graduated target.

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I would say it’s not necessary in F Class. You know the distance and the scoring rings correlate to MOA

Carl N. Brown said:

I think pi (3.14159 to infinity) is involved. A radian is a section of a circle whose arc is egual in length to the radius, or, shaped like a slice of pi.

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Yes, there are 2*Pi radians = 6,2831853072.. rounded to 6238 mRad in a circle.

The Swedish Army decided that was to complicated so they defined a circle to be 6300 MIL, the US and henceforth NATO thought even that to be too hard to divide in your head and settled for 6400 MIL in the circle and these are what's used for artillery.

The USSR simplified things even further by having 6000 MIL in a circle

So first of all you need to decide which of all these MILs you want to use.

The forte of using MIL or mRad shows when your using the metric system.

For small angles there's negible difference between the length of the spanned circumference and a line perpendicular to the line of aim, so 1m off center at 1000m equals 1 mRad for all normal purposes.

1cm at 100m is .1 MIL And if that's one click on your scope, then life is sweet.

For imperial distances MOA works better with 1" at 100 yards equivalent of 1 MOA IIRC

I have a bunch of military compasses graduated in 6300 MIL, I use them for the cub scouts where we only talk north and south etc.

I even have a few with the infamous "New degrees" with 400 degrees in the circle, they're useless for everything.

The biggest reason to take Mil based scopes has nothing to do with math, ease of use of a 10 based # system, or metrics vs imperial measurements. But it does have a bunch to do with how scopes are constructed.

Take two scopes, both with say a common 100 spline turrets. On a 0.1 Mil (0.36" per click or spline notch) adjusting scope you will get 10 mils per rotation, equaling 34.38 MOA. Now made that same scope in MOA, with common 1/4 MOA per click or spline notch, on 100 spline turret, you'll get only 25 MOA ( or 7.27 Mils per rotation).

All this means you'll get less adjustment per each turret turn, and it makes it both easier to get lost on what rev your at, and many scopes have rev limiters, so you'll not get as much of the needed adjustment to reach really long ranges.

If you design a scope with 1/2 MOA adjustments, then a MOA scope will take the lead, but many feel that's too coarse for fine work LR work.

Ryden said:

Yes, there are 2*Pi radians = 6,2831853072.. rounded to 6238 mRad in a circle.

The Swedish Army decided that was to complicated so they defined a circle to be 6300 MIL, the US and henceforth NATO thought even that to be too hard to divide in your head and settled for 6400 MIL in the circle and these are what's used for artillery.

The USSR simplified things even further by having 6000 MIL in a circle

So first of all you need to decide which of all these MILs you want to use.

The forte of using MIL or mRad shows when your using the metric system.

For small angles there's negible difference between the length of the spanned circumference and a line perpendicular to the line of aim, so 1m off center at 1000m equals 1 mRad for all normal purposes.

1cm at 100m is .1 MIL And if that's one click on your scope, then life is sweet.

For imperial distances MOA works better with 1" at 100 yards equivalent of 1 MOA IIRC

I have a bunch of military compasses graduated in 6300 MIL, I use them for the cub scouts where we only talk north and south etc.

I even have a few with the infamous "New degrees" with 400 degrees in the circle, they're useless for everything.

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Not so. A Mil is one, one thousand of any measurement. So a Mil is: 1 inch at a 1,000 inches, 1 meter at a 1,000 meters, 1 yard at a 1,000 yards, 1 cubit at 1,000 cubits, 1 furlong at a 1,000 furlongs and so on.

Another fallacy is your instance that 1 MOA is the same as 1". No it's not. One MOA is 1.047". Then you going to say the difference between inches and MOA is only 0.5" at 1,000 yds.

But your scope adjustments can compound that small error. A cartridge like the 308 winchester shooting a 175 grain SMK @ 2700 fps will drop 388.5 inches at 1,000 yds. In MOA that will require 37.1 MOA of up adjustment. However in inches/per100 yds that will require 38.9 inches of up adjustment.

The difference between them is 1.8" x 10 or 18 inches of error you would be introducing. At 500 yds it would be 9" of error.

MOA does not work better than Mils at any range for any purpose. Both will get you to the same place hit wise, if used intelligently, but sloppily comparing imperial inches as absolutely equal to any MOA values at any range will get you a miss more often than not.

BobinNC said:

Not so. A Mil is one, one thousand of any measurement. So a Mil is: 1 inch at a 1,000 inches, 1 meter at a 1,000 meters, 1 yard at a 1,000 yards, 1 cubit at 1,000 cubits, 1 furlong at a 1,000 furlongs and so on.

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Um... Nah, bro....

In this industry, it is painfully obvious to all of us that a “Mil” is short for a milliradian... and the provided definitions for milliradians above are apt...

“Milli-“ as a prefix means “one one thousandth,” not “one, one thousand.” Everything you implied then as 1” out of 1,000” and furlongs etc is silliness thereafter. A milliradian is a fractional radian, which is a unit of ANGULAR measure. Everything you’re implying as radians of linear measure is false.

The 1.8” and 18” thing thereafter is seriously broken understanding of math as well... you’ve stepped in something and can smell something, but you’re not quite sure what it is yet, so please refrain from this kind of chest thumping until you really understand what’s on the bottom of your shoe...

How about some facts instead of insults, Bro.

I'm not implying radians is a linear unit of measurement, I'm apply Miliradian's as they are intended to be used in conjunction with linear values.

My illustrations were not silliness, but an explanation of how the Milliradian concept can be applied and worked with any linear unit of measure you choose to apply it too.

Or do you think that, 1 Mil equaling 1 yard @ 1,000 yds, and that also 1 Mil equaling 1 meter @ 1,000 meters, is just some sort of a odd coincidence?

Please explain where my math is wrong, but you haven't, because you can't.

Base 10 unit systems have a tendency to create base 10 relationships. Ratios are what they are, afterall. Radians are based on the relationship of a circumference to its radius - inherently dependent upon pi, a fixed scalar ratio, so dividing a fixed ratio by 1000 will yield a relationship of 1000 in or out... not coincidental.

But angular measures are angular measures. They relate to linear measures only by relativisms, without a basis unit of linear dimension, milliradians would not relate to length (in lay terms, you must have a length AND an angle to determine linear dispersion, otherwise an angle is just an angle). Milliradians are derived units for angular dispersion. We USE angular units to relate linear proportions, but angular units can and do exist without linear dimension.

I think some of this comes from the use of small angle approximations of trig functions that many have forgotten are baked into many of these calculations we do in our heads.

If my bullet impacted 1 yard from my point of aim at 1000 yards then my angular error would be, theta = acrtan (1/1000) which is .0009999996666... radians.

But at small angles you can approximate tan(x) = x. It is usually considered acceptable to do this with angles less that .1 radians, with the approximation tan(.1) = .1 having and error ~.33% error with the error getting smaller as the angle gets smaller. The small angle approximation works for the inverse trig function arctan(x) = x also, again at small angles.

So theta = arctan (linear-error/range) becomes simply theta = linear error/range. As you can see the error for using this small angle approximation is very small.

It is also the exact formula for calculating the arc length at that radius (range). L = r (theta). Solve for theta and we are saying the arc length is approximately equal to the linear distance (cord) of that arc. Again at very small angle not a bad approximation.

The forum interface really sucks for doing math, we need some greek letters!

OK: Α α, Β β, Γ γ, Δ δ, Ε ε, Ζ ζ, Η η, Θ θ, Ι ι, Κ κ, Λ λ, Μ μ, Ν ν, Ξ ξ, Ο ο, Π π, Ρ ρ, Σ σ/ς, Τ τ, Υ υ, Φ φ, Χ χ, Ψ ψ, and Ω ω.

Carl N. Brown said:

OK: Α α, Β β, Γ γ, Δ δ, Ε ε, Ζ ζ, Η η, Θ θ, Ι ι, Κ κ, Λ λ, Μ μ, Ν ν, Ξ ξ, Ο ο, Π π, Ρ ρ, Σ σ/ς, Τ τ, Υ υ, Φ φ, Χ χ, Ψ ψ, and Ω ω.

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Cool how did you type all those in?

I copied the Greek alphabet listing at Wikipedia, pasted it in notepad, copied it from notepad and pasted it in the comment box.

There are probably Alt- numeric codes for the symbols but I haven't needed them and didn't learn them.



I saved a file greek2me.txt in my \manual\ folder on my laptop. Won't help me on the phone.

BobinNC said:

MOA does not work better than Mils at any range for any purpose

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Most High Power and Bench Rest competitors would disagree with you on that point

At the Wikipedia article on milliradians:
The true definition of a milliradian [mrad] is based on a unit circle with a radius of one and an arc divided into 1,000 mrad per radian, hence 2,000 π or approximately
_ 6,283.185 milliradians in one turn [circumference],
and rifle scope adjustments and reticles are calibrated to this definition.
There are also other definitions used for land mapping and artillery which are rounded to more easily be divided into smaller parts for use with compasses, which are then often referred to as "mils", "lines", or similar.
For instance there are artillery sights and compasses with
_ 6,400 NATO mils,
_ 6,000 Warsaw Pact mils, or
_ 6,300 Swedish "streck" per turn [circumference]
instead of 360° or 2π radians, achieving higher resolution than a 360° compass while also being easier to divide into parts than if true milliradians were used.

True millirads are 3.4377469.... minutes of angle.
The Warsaw Pact mils are 3.6 minutes of angle.
NATO mils are 3.375 minutes of angle.
Swedish "streck" are 3.428571... minutes of angle.

And 1 MOA equals 1.047 inches at 100 yards.

Carl N. Brown said:

For instance there are artillery sights and compasses with
_ 6,400 NATO mils,

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Pre - NATO, the Artillery mil was 6400 to the circle, the Infantry mil was 6280, closer to the geometry.

BobinNC said:

Not so. A Mil is one, one thousand of any measurement. So a Mil is: 1 inch at a 1,000 inches, 1 meter at a 1,000 meters, 1 yard at a 1,000 yards, 1 cubit at 1,000 cubits, 1 furlong at a 1,000 furlongs and so on.

Another fallacy is your instance that 1 MOA is the same as 1". No it's not. One MOA is 1.047". Then you going to say the difference between inches and MOA is only 0.5" at 1,000 yds.

But your scope adjustments can compound that small error. A cartridge like the 308 winchester shooting a 175 grain SMK @ 2700 fps will drop 388.5 inches at 1,000 yds. In MOA that will require 37.1 MOA of up adjustment. However in inches/per100 yds that will require 38.9 inches of up adjustment.

The difference between them is 1.8" x 10 or 18 inches of error you would be introducing. At 500 yds it would be 9" of error.

MOA does not work better than Mils at any range for any purpose. Both will get you to the same place hit wise, if used intelligently, but sloppily comparing imperial inches as absolutely equal to any MOA values at any range will get you a miss more often than not.

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Well, strictly speaking a mil is 10 km, but if you state that a milliradian is 1 whatever at 1 000 whatevers that's true. But only for small values of milliradian. (See MCB's excellent post on small angle approximations)

If you're 1 571 mRad off at 1 000 m, you're definitely not 1.571 m off target, you're shooting at 90° to it.

It's also true that 1 MOA isn't exactly 1"@100y, that's a simplification on my part.

But in real life?

If you're 2" off at 100 yards with a 1/4" per click scope, how many clicks will you adjust with 1.047/4" per click vs. 1/4" per click?

With 1/8" per click I give you the extra click for better precision, but I've only seen such a scope on a hunting rifle once in my life and it wouldn't work very well for long range shooting.

If you're calculating the drop at 1 000 yards you don't do it in your head, I can't anyway.
You use a BC, and then it's a moot point which system is easier for use by rule of thumb.

You really can't extrapolate a given statement like that because you end up in a quagmire of significant numbers.
I stated that there was equivalency at 100 yards when adjusting a scope, which for all intents and purposes there is.
You really don't measure your target with three decimal precision do you?

And i very much doubt that the drop at 500 yards is half of the drop at 1 000, that would imply that the tracectory is a straight line instead of a parabola, and that theory was dead even in the 1500's.
There's a manuscript on ballistics showing the trajectory of a cannon as going up in a straight line until all the energy is spent whereupon it drops straight down.
I imagine the scholars of those days having much the same kind of arguments as the internet is full of today

Everybody be friends

Sorry, it's 5 am here and there's a bloody (or soon to be of i can only spot it) woodpecker been going at it hammer and tongs for the last hour and a half behind my bedroom.

Makes you the tiniest bit cranky...

Legionnaire said:

So much for “no debate.”

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that was always an aspirational goal

Legionnaire said:

So much for “no debate.”

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There is no debating that I have found the best deals on MOA scopes so that’s what I buy.

I almost had a MIL Razor HD, but did not make the sale in time.

I had the thought of getting a MIL scope, to talk the same as any other aspiring Long Ranger, but circumstances are making it increasingly far fetched.

Benches, however, are perfectly suited to MOA discussions.

Legionnaire said:

This entire discussion has been instructive and confirming to my thinking. My takeaways:

• MIL and MOA are two means to the same end
• Social context matters. If you're shooting by yourself, pick which ever you are more comfortable with; if you are shooting socially, there is some advantage to using the same metric as those around you so you're speaking the same language
• PRS-type shooters, aspirants, and wannabes (self included) tend to favor MILs; Benchrest tends to favor MOA.
• One can do a lot with a basic crosshair or duplex reticle, especially with solid, repeatable turrets

At the end of it all, the only scopes I don't have much use for are those with BDC reticles. I'd rather have straight MIL or MOA stadia.

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Well said.

I am the same way and don't care for any of the BDC reticles that I have tried. The only exception to that is the Swampfox Blade 1X prism with bullet rise compensator reticle, but that doesn't fit into this conversation.

Now whether I use a MOA or MIL reticle, I DO want the turrets to match.