Rifle Scopes Why most of us have MIL scopes but accuracy is expressed in MOA?

[Alex V]

I'll be the first to admit that when i first read your post, it apeared that you were trying to say that mils is a metric system measurement. After rereading a few times, i stand by what i said that something got lost in translation. i now see you were just making an argument about why using the metric system is easier. i get that now and i dont disagree, but here in the US i guess we are stuck with imperial so we may as well just use that here. i would love to switch to metric, but i also know that isnt as easy as congress just making it so. it would be a monumental undertaking to say the least.

Thank you!

You are right, making the US switch the metric system isn't going to happen. Most people have no concept of what a meter is. I remember my coworkers having a really hard time when we were working on European and Asian projects and all the dimensions have to be in in mm. It was a whole new language. I just don't understand why. It's all base 10. Tell them that a door is 915mm and they freak out. Calm down, its just a 3' door. When they would see 3200 for a floor to floor dimension they would be beside themselves. Calm down, its 10'-6" LOL

 

[BobinNC]

I love it when somebody says both MIL adjusting and MOA adjusting scopes get you to the same place, and one system is not better than the other.

But everybody forgets about scope design. An elevation turret only has so many splines. So a 10 mil turret, that adjusts 0.1 Mils per click has 100 splines, allowing 36" of adjustment @ 100 yds or correcting for 360" of drop @ 1000 yds. Change the turret to MOA and you still have 100 splines, that adjust in .25 MOA clicks, allowing 25 MOA (26.175") of adjustment @100 yds or correcting for 261.75" of drop @ 1000 yds.

That is the big limitation to a MOA vs MIL adjusting scope. For example the popular Mil version of the DT S&B 5-25x56mm at 0.1 Mils per click has 26 Mils of adjustment, and the MOA version at .25 MOA per click has 65 MOA

 

[Deleted member 10043]

Explain why .1 MIL = .xx MOA ?

 

[CharlieNC]

Back to the original question, NRA target scoring rings are in moa increments, and are consistent from short to long range. NRA classification is based upon how well one scores against this standard.

 

[Ledzep]

Explain why .1 MIL = .xx MOA ?

A radian, the System International ("metric") unit for angles, subtends around the arc of a circle the same distance as the radius of the circle. Because the circumference of a circle is 2*pi*radius, there are 2*pi (6.2831) radians in a circle. "Milli" is the SI ("metric") prefix for 1/1000. Thus there are 1000 milliradians in 1 radian, and 6283.1 milliradians in 1 complete circle.

A "Minute of angle" is 1/60th of 1 degree (the English/standard unit for angular measure). As such, there are 60*360=21,600 Minutes in 1 full circle.

So considering a full circle is 6283.1 milliradians and 21,600 minutes, and both units measure the same thing (angles), a simple ratio can be used to convert between the two. 1 milliradian = 21,600 MOA/6283.1 milliradian = 3.4378 MOA.

0.1 milliradians then, would be 0.34378 MOA.

 

[_Windrider_]

A radian, the System International ("metric") unit for angles, subtends around the arc of a circle the same distance as the radius of the circle. Because the circumference of a circle is 2*pi*radius, there are 2*pi (6.2831) radians in a circle. "Milli" is the SI ("metric") prefix for 1/1000. Thus there are 1000 milliradians in 1 radian, and 6283.1 milliradians in 1 complete circle.

A "Minute of angle" is 1/60th of 1 degree (the English/standard unit for angular measure). As such, there are 60*360=21,600 Minutes in 1 full circle.

So considering a full circle is 6283.1 milliradians and 21,600 minutes, and both units measure the same thing (angles), a simple ratio can be used to convert between the two. 1 milliradian = 21,600 MOA/6283.1 milliradian = 3.4378 MOA.

0.1 milliradians then, would be 0.34378 MOA.

The wiki force is strong with this one.

 

[Gunfighter14e2]

Who here has a TO&E book that lists the size of everything in mil?

 

[TripleBull]

lol Mils are not metric?

Look up the SI unit for angles, and SI prefixes...

I brought this up earlier. If you believe that NIST understands what is meant by "modern metric", then, yes, mils are metric units.

The radian is an SI unit for measuring angles:

https://physics.nist.gov/cuu/Units/introduction.html

https://physics.nist.gov/cuu/Units/units.html

https://en.wikipedia.org/wiki/Radian

 

[spife7980]

But is is a mathematically derived unit and not based on one of their fundamental units of measure.

Both camps can lay claim to be correct depending on their perspective. None of this unit taxonomy has any real relevance on the question though.

I can count dimes just as well as I can count quarters. The unit only matters if it matters to you. We stick with convention as thats what we are used to end of story.

 

[scudzuki]

I don't express precision in MOA, I use IPHY, for example, .60" five shot group at 100 yards.
Some of the scopes in the configuration I want are only available in milliradians.
Milliradians is base 10 and as LL pointed out, most of us have used base 10 math all our lives.
If you want to range using your reticle, the fact that 1 mil subtends to 1/1000th the distance makes the math easier, especially valuable if you're doing it in your head.

 

[Deleted member 10043]

So, you telling me I have been basically using a scope with more than 1/3 MOA clicks?

 

[TripleBull]

most of us have used base 10 math all our lives.

I'm ambibasedextrous. I'm comfortable with feet, meters, Kelvins, radians, binary numbers, whatever. I do shots of tequila without worrying about the standard that produced the size of the shot glass as long as it's not that Montezuma swill that tastes like you accidentally got brake cleaner in your mouth.

 

[Subwrx300]

Sooooo, I've got a sub-MIL rifle. It shoots easily .5 MIL all day long every day! $10k... Joking.

I think to the OP's original thoeretical question (why do we express accuracy in terms of MOA regardless of the scope adjustment system we use), it's a valid point but the "why" does seem rooted in NRA plus easier reference to units we use each day. My first sentence was obviously intended as joke but makes a simple point about the ease of discussing half or quarter of some standard. (I.e. half MOA vs .~.139MIL)

There is some merit to using the mil variant of sub .1, .2 or .3 MIL thresholds but then again it's marketing and common reference points. I believe a few years back a similar post was going around and a European shooter jumped in that they do in fact use MIL reference with respect to precision.

But the pointless circlular discussion continues... Pun intended. ?