Rifle Scopes Ranging with mils

[remaction]

What easy "in the head" math is there for ranging in mils?

I have read a few different publications that have different methods, but one way I've come up with (I guess it all depends on how accurate you need to be) is to take the number of inches that one mil covers on the target divided by 4 + 10% = yards in hundreds (this is based on one milrad equaling 3.6" at 100 yards).

For example, a fence post is near the target and you know the fence post is about 4' out of the ground. If one mil covers 1/2 the post, that is 24". 24 / 4 = 6 + 10% (easy calc to account for the 4 being about 10% over the 3.6" mil coverage at 100 yd) = 6.6 or 660 yards (6.6x100).

That's about as easy as I've been able to make it in my mind, but it depends on knowing the height or width or the target or something near it. I've found it's sometimes easier to halve the inches twice if you get an odd number (half of 24 is 12 and half of 12 is 6 + 10%).

Is there any easier way?

 

[Lindy]

Re: Ranging with mils

Get a Mildot Master.

 

[myerfire]

Re: Ranging with mils

For example, a fence post is near the target and you know the fence post is about 4' out of the ground. If one mil covers 1/2 the post, that is 24". 24 / 4 = 6 + 10% (easy calc to account for the 4 being about 10% over the 3.6" mil coverage at 100 yd) = 6.6 or 660 yards (6.6x100).

The above formula sounded great at first. I started to run some samples and started getting a headache. Lindy has the right approach, a Mildot Master is the way to go.
myerfire

 

[Lindy]

Re: Ranging with mils

Well, another thing you can do is to make a spreadsheet.

In the left-hand column, let's say column A row 3, put increments of milliradian readings, like 0.1 mil.

In subsequent columns, says starting with Column B, put increments of, say, inches, starting with maybe 6 inches if that's the smallest target you'll be shooting at and having to range. I'd increment the target size by 2 inches, rather than one, and you can just interpolate between columns. So, column C would be a target size of 8 inches, and so forth.

So, the cell in column B, row 3, would correspond to 0.1 milliradian for an image size, and 6 inches for the target size.

For each cell, use the mil formula. For cell in colum b, row 3, which corresponds to an image size of 0.1 mil and a target size of 6 inches, the formula will look like this:

$B$2*27.77/$A3

Then copy that formula all the way down that <span style="font-weight: bold">column</span>, until it's in all the cells for however far down you want to go with image size.

The next colum over, column C, which corresponds to a target size of 8 inches, will look like this:

$C$2*27.77/$A3

When you get done, you'll have a handy reference which looks like this:
<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
Target size (Inches)
Mils 6 8 10 12
0.1 1666 2222 2777 3332
0.2 833 1111 1389 1666
0.3 555 741 926 1111
0.4 417 555 694 833
0.5 333 444 555 666
0.6 278 370 463 555

</pre></div></div>

The cells have range in yards. And you can carry that out as far as you care to.

Some sniper data books have charts like that, but you can make your own using this procedure if you don't have one.

If you are Excel-challenged, you can download the quicky one I created from:

http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Excel/MilRangingYards.xls

It covers image sizes from 0.1 to 2.8 mils, and target sizes from 6 inches to 34 inches in increments of 2 inches. You can pretty it up, and print it however you want.

 

[Wil]

Re: Ranging with mils

DUDE!

you make my head hurt....lol

I'll stick with the MilDot master... or memorize it

 

[Lindy]

Re: Ranging with mils

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">you make my head hurt....lol</div></div>

Thanks! That's my job!

And I use a Mildot Master.

 

[Unsichtbar]

Re: Ranging with mils

Consider this 4" is 100mm which if it subtends 1 mill it is 100 Meters Range. Now if the target is say 12"/4= 3(100mm units) which is 300 Meters Range. What ever the target is in mm if it subtends 1 mil that is its range in meters. A meter long ruler is 1000mm so if subtends one mil it is 1000 meters.

If that same 12" target which =300mm = 300 meters subtends 2 Mills it is 150 meters away.

Just remember 4" is aprox. 100mm or 10cm and there is 25.4mm to an inch

Lindy might have a more eloquent and coherent way of expressing this

 

[Lindy]

Re: Ranging with mils

A milliradian is an angle which subtends an arc which is 1/1000th of the distance to the vertex. And it doesn't matter whether you measure that in inches, yards, or meters.

I'm still gonna use my Mildot Master.

 

[remaction]

Re: Ranging with mils

I checked out the Mildot Master website and I think I will get one for use.

However, to me will be more useful when you have the time to pull out the card, take the measurement in the scope, pull out the reading glasses (unfortunately I'm getting older) to move the mildot master to the correct setting and get the corresponding range, then pick up the rifle again, adjust the hold and shoot.

My original question was more from a "there it is, how far is it, adjust, shoot" standpoint where I can do the math quickly in my head without taking my eye off the target or setting the rifle down. I see the elk on the website and I say 1 mil is 15" of body / 4 = 3.75 + .4 (10% or .375 rounded up for easy adding) = 415 yards.

Is there an easier "in the head" method that I should try?

 

[LoneWolfUSMC]

Re: Ranging with mils

I used a calculator or paper for years. When it was nasty, a grease pencil on your map works (or just use the map).

Now that I know they exist the Mildot master appears to be the best non-battery method. I love how it's got the slope calculations built in.

As far as "in the head" if you use a fixed magnification optic it is possible to get used to the size of targets in the field and guesstimate off of that. I preferred to use the Mk1 Mod0 eyeball and the "football field" method for closer ranges (where range errors are less drastic).

When all else fails I always have the formula in my brain and although it's not quick I can do the math in my head.

 

[Unsichtbar]

Re: Ranging with mils

I also have a Mildot Master, good tool use it every time I get and use it every time I get a chance, alot to be said for it. Sure there is more to range estimation than a mildot. Experience what features can be made out at what range etc. Hell if there is a laser about, a topo map, GPS or a tape measure. I also have a chart taped to the rifle that does not require a hand to manipulate.

What ever works for you I fine. the milliradian/meter thing is easy for me and I am aware at a milliradian can be use with any unit of measure. The OP looks like he got he has a system that works just a question of which units and head math he prefers.

 

[JuniperEyes]

Re: Ranging with mils

A mil is 3.6 inches at 100yds, 7.2-200, 10.8-300, 14.4-400, 18-500, and so forth.

Knowing this, if the fencepost were 3ft high instead of 4ft, it would be 2000yds distant if it covered .5 mil, as a mil is 36in at 1000 yds.

Since in the example the fencepost covers only half a mil and is 48 inches tall it is over 2000yds away, as a mil is 72 in at 2000, so half mil is 36 inches at 2000yds.

Split the difference and derive just over 2500 yds to the fencepost.

Long damn ways away...

Suppose the fencepost covered 2 mils.

Fencepost is 48inches. Mil is 36in at 1000yds, so 2 mil is 36in at 500yds. Fencepost is 1/3 more height than 36 inches, then target is 1/3 farther than 500yds. From this we get a little over 650yds to target.

I am new to this, but these estimations have been getting me pretty close as complex math in my head is out of the question for a dumbass like myself.

I also use the mildot master but have been working on this method for using as a crutch if the master is not available.