Mil / MOA calculation. Yes, again....

[tqlcvnch]

I've been using MOA scope and gotten used to the 1" @ every 100 yards assumption. Recently I'm a little intrested in the MilRad system. So can someone confirm whether the following calculation/assumption is correct?

1.) Doesn't matter what unit system (inch, yards, meter, banana-length, etc.), each "mil" is 1/1000th of the distance to target?
2.) 1 mil at 100 yards = 1/1000th of that 100 yard = 0.1 yard = 3.6 inch (since there's 36 inches in a yard, and 0.1 x 36=3.6")?

So....for 100 meters, 1 mil = 0.1 meter = 1 cm? Let's say I hit 2 cm left of the bullseye, I have to adjust the windage 2 mils to the right to correct it?

 

[JohnMWoo]

I've been using MOA scope and gotten used to the 1" @ every 100 yards assumption. Recently I'm a little intrested in the MilRad system. So can someone confirm whether the following calculation/assumption is correct?

1.) Doesn't matter what unit system (inch, yards, meter, banana-length, etc.), each "mil" is 1/1000th of the distance to target?
2.) 1 mil at 100 yards = 1/1000th of that 100 yard = 0.1 yard = 3.6 inch (since there's 36 inches in a yard, and 0.1 x 36=3.6")?

So....for 100 meters, 1 mil = 0.1 meter = 1 cm? Let's say I hit 2 cm left of the bullseye, I have to adjust the windage 2 mils to the right to correct it?

1 mil @ 100 yards = 1/1000 of 3600" = 3.6 inches. It is 1/1000.

At 100 meters, 1 mil = 0.1 meters = 10 cm (not 1 cm).

If you hit 2 cm left, you would move 0.2 mils (not 2 mils). Most mil scopes' "click" values are 0.1 milirad, so 2 clicks right.


These equations might help:
1 moa = 1.047" @ 100 yards
1 mil = 3.6" @ 100 yards
1 mil = 3.438 moa

The decimal places out to the +/- 0.001 can matter at extended ranges.

R,
J Woo

 

[ShootinAlphas]

That is the jist of it. And the thing with Mil adjustments is that you almost always have a reticle with good, mil-based subtensions to work with.

So instead of worrying about correcting based on math, just read your reticle. If your bullet impacted 2.5 mils low and .5 mils left based on your reticle, then either come up 25 clicks and right 5 clicks or just hold off.

 

[tqlcvnch]

Thank you, John & ShootinAlpha. The reason I ask is to know how much to compensate the bullet drop based on ballistic calculations before making the first shot.

I forgot that 0.1 = 10% (not 1%). So at 100 yards out, 1 mil = 10cm. So then at about the same distance to target 100yards/100meters an increment of 1 mil is quite larger than 1 MOA. So, MOA seems like a "finer" unit. Then my next question is.....Is it worth to join the rest of the world in using MilRad and getting my next scope in that measurement/system or just stick with MOA since I don't shoot outside the USA anyway?

 

[JohnMWoo]

Thank you, John & ShootinAlpha. The reason I ask is to know how much to compensate the bullet drop based on ballistic calculations before making the first shot.

I forgot that 0.1 = 10% (not 1%). So at 100 yards out, 1 mil = 10cm. So then at about the same distance to target 100yards/100meters an increment of 1 mil is quite larger than 1 MOA. So, MOA seems like a "finer" unit. Then my next question is.....Is it worth to join the rest of the world in using MilRad and getting my next scope in that measurement/system or just stick with MOA since I don't shoot outside the USA anyway?

At any distance, 1 mil is "larger" than 1 moa. 1 mil = 3.438 moa.
1 moa is a smaller angle than 1 mil, so I guess you could say it is "finer".

Scope reticles and turret "click" values are divided mostly so that the subtensions are about equal. So it really just depends upon your personal preference, or what your team uses so you can communicate effectively.
Just make sure you either go with a reticle/"click" of moa/moa or mil/mil.

R,
J Woo

 

[M40_A1]

I forgot that 0.1 = 10% (not 1%). So at 100 yards out, 1 mil = 10cm.

NO!!! He's wrong and is confusing you!

You were right the first time. A mil is 1/1000 the distance, AT ANY DISTANCE. But you CANNOT mix systems. 1/1000 of 3600 INCHES is 3.6 INCHES. 1/1000 of 100 METERS IS .1 METERS, which translates to 10 cm.

A mil at 356 meters is .356 meters. A mil at 782 yards is .782 yards (or .782yds. x 36" = 28.152", or 3.6" x 7.82 = 28.152", if you prefer). Easy-peasey.

And, BTW, yes, 0.1 IS 10% of 1. But you want 1/1000 (.001) of your range, or .1% (1/10 of 1%), not 1%!

 

[JohnMWoo]

NO!!! He's wrong and is confusing you!

You were right the first time. A mil is 1/1000 the distance, AT ANY DISTANCE. But you CANNOT mix systems. 1/1000 of 3600 INCHES is 3.6 INCHES. 1/1000 of 100 METERS IS .1 METERS, which translates to 10 cm.

A mil at 356 meters is .356 meters. A mil at 782 yards is .782 yards (or .782yds. x 36" = 28.152", or 3.6" x 7.82 = 28.152", if you prefer). Easy-peasey.

And, BTW, yes, 0.1 IS 10% of 1. But you want 1/1000 (.001) of your range, or .1% (1/10 of 1%), not 1%!

Thanks. My misread. Corrected.

R,
J Woo

 

[M40_A1]

Thanks. My misread. Corrected.

R,
J Woo

I figured you didn't mean to say it. Sorry if I came across a bit harsh.

 

[Kiwigrunt]

For the metric approach, I think it may pay to skip the centimetres. Go straight to millimetres.

1 milliradian is in millimetres on the target, what the range is in meters.
So at 100 metres, 1 milliradian is 100 mm.
At 758 meters, 1 milliradian is 758 millimetres. (So 1 click on most mil scopes would give you a 76 mm or 3" shift in this case.)
Because 1 mm is 1/1000 (1 permil, see below) of 1 m. So the factor of 1000 is already built in if you go straight from m. to mm.

Therefore, at 245 gumboots, 1 milliradian is 245 milligumboots.
At 45836 inches, 1 milliradian is 45836 milli-inches (commonly referred to as 'thou')


A bit more useless information:
1/100 is 1 percent (1 %).
1/1000 is 1 permil (there's that mil again) (also spelled as per-mille) (1 ‰).


Is it worth joining the rest of the world by going milrad? Only you can answer that for yourself.
The fact that 1 moa seems a 'finer' unit than 1 milrad is the wrong reason to prefer one over the other. 1 cm is a 'finer' unit than 1 inch. So what? For all the reasons conceivable to prefer metric over imperial, that is not one of them. For as far as scope use is concerned, it is the way we cut those units up that makes the difference in ease of use. Decimals (0.1 milrad clicks) are easier (for most) to work with than fractions (1/4 or 1/8 moa clicks). That's a big thumbs up for milrad scopes.
The advice given in post 3 is pertinent, and also works (of course) for moa/moa scopes; but easier with milrad scopes because of those decimals rather than fractions.

Compensating the bullet drop based on ballistic calculations works in either system. Just tune the system to the scope and units you use.

My next suggestion pains me, and I really want someone to rebut it.
If you are one of the many people who keep falling back to the inch over yards crutch to make sense of angles, you may perhaps be better served with a moa/moa scope. That crutch is not a crime. If it works for you, then it works for you. That said, the only way to get more comfortable with angles is to immerse yourself in it. That immersion can consist of reading the insidious crap that others and I throw at you (including some good vids), or (inclusive or) trying to force yourself to think in angles rather than linear when behind the musket. Now for a cheap pun, at some point those angles may just click. I immerse myself in it by writing these kinds of posts, and I learn from it. So thank you all for being the involuntary cause of my own learning.

 

[tqlcvnch]

I kind of getting a hang of it now. Thanks a lot to all of you for taking the time explaining MilRad to me in full detail! I think you've cleared my confusion and I understand the concept behind it now.
The reason I'm thinking of switching to Mils is because I'm really digging the "MSR" reticle....Now I'm fighting myself to choose among S & B , Steiner, and Kahles....


Thanks again, all!

 

[damoncali]

My next suggestion pains me, and I really want someone to rebut it.
If you are one of the many people who keep falling back to the inch over yards crutch to make sense of angles, you may perhaps be better served with a moa/moa scope. That crutch is not a crime. If it works for you, then it works for you. That said, the only way to get more comfortable with angles is to immerse yourself in it. That immersion can consist of reading the insidious crap that others and I throw at you (including some good vids), or (inclusive or) trying to force yourself to think in angles rather than linear when behind the musket. Now for a cheap pun, at some point those angles may just click. I immerse myself in it by writing these kinds of posts, and I learn from it. So thank you all for being the involuntary cause of my own learning.

No, that's a plenty good suggestion. There's nothing wrong with MOA. I prefer them myself because I hate the metric system. I just do. I get really tired of being off by a factor of ten when thinking quickly. I finally embraced my imperial nature. And before someone says "MILS AREN"T METIC!", 1) They are. And 2) I don't care because I sure as heck don't measure range in inches or targets in yards. You might get me ranging in meters, but then I"m back to "centimeters or millimeters or decimeters or what" for target sizes.

Maybe I'm a little jealous of people who don't get all screwed up over metric stuff, but I'm just not one of them. I can live with that.

And for the "just measure the angle" crowd, try that with irons or a plain cross hair. Knowledge is power.