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#### tylerw02

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I was doing some math and this can be done with any mil or MOA scope calibrated at any power, or at least I think....If somebody can verify, that would be great.

I've been considering getting a 3.5-15x50 NF NXS with NRP1 (1moa scale) and wondered if I could do this same trick with that optic....and sure enough, you can.

First, we know that 1 mil=3.43775 moa

We know the style scope mel mentions is set for 10x.

So if we investigate, a 72" target=6.8755 moa at 1,000 yards [72"/(1.047 *10)]@1000 yards.

The values are then doubled at 5x, 1 mil=6.8755 moa. At 5x, the target should read 2 mils for a 500 yard range.

So, we know we can take the formula, 72"/(1.047*5)=13.75 MOA. At 500 yards, the mils read 6.8755 moa each, therefore two are 13.75 moa, just as the formula predicts.

So how does this work with your scope you ask? Well if you have a 3.5-15x50 NF NXS and the 1 moa scale, you can apply the same logic without converting anything to mils.

At 1500 yards, 1 moa=15.705" per previously established formula. Therefore, 72"/15.705"=4.58 moa. On the NF NPR1, its read in 1 moa increments, so a 72" target should take up approximately 4 1/2 tics.

To check this for other ranges, we can convert our moa scale for the different powers. So if the scope (which it is) is set to for the moa scale to work at 15x, we know that 15/10=1.5...so on 10x, the tics are 1.5 moa apart. At 6.5x, they are 2.3 moa apart.

So let's use the same logic over again to check. So theoretically, if we dial down to 10x, the target should take up the same 4.58 moa at 1,000 yards. Let's check it out...at 1,000 yards, we already know a 72" target is 6.8755 moa. We also know our tics are 1.5 moa apart now. So we can divide 6.8755 by 1.5 moa and get 4.58 moa, just as predicted.

Let's work it over again with the dial at 6.5x. At 650 yards, a 72" target is 72"/(1.047*6.5) to get 10.5796 moa. At 6.5x, we can find our scale now reads (15/6.5) 2.3077 moa per tick. So we can take 10.5796 moa (size of the 72" target) and divide by 2.3077 to get 4.58 moa yet again, or approximately 4.5 tics at 6.5x at 650 yards.

So the goal here is to fit the target into about 4.5 tics for a close approximation. We can take the power reading when the target fills 4.5 tics and multiply by 100 to get a quick range estimation.

After trying it several ways, I'm pretty sure this method will indeed work. If anybody can find flaws with it, please let me know. If not, looks like a good quick and easy no-math way of ranging with ANY calibrated scope so long as you can work out the math one time.

#### monteboy84

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Sticky'd, thanks for the write-up Tyler, your math looks good 8)

-matt

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The maths looks good to me too. Great write up, thanks!

#### tylerw02

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No problem!

#### Banshee

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Nice work

This is some good info. I shows me 3 things. #1) This sight takes tactical shooting to heart. #2) Unlike me some people like math. :lol: #3) I need to get my butt out to refresh me mil-dot work. :roll: NICE JOB loving the sight.

#### RIO177

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Thats correct. Just remeber to use the power setting as the multiplier for your constant.

size of target x constant (power setting) divided by height in mils= range.
.its easy for me as an expediant method for fast ranging of human. mid waist to top of head is 1000..or 100 or 10 or I like to use 10 at 10x because its easier to think of 10 that 1000 0r 100.. ( just a mental thing) divided by the mil . So a human from waist to head is always 10 ( if at 10x) divided by mils.. so if 3 mils 10/3 mil =333 if scope at 5x 5/1.5 mil= or 333 etc..this is for second focal plane scope as it will not matter with the power settings on 1st focal plane optics.

#### Savage110

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Ok so I feel dumb for asking this but, in this formula, where do you get the
1.047??

First, we know that 1 mil=3.43775 moa

We know the style scope mel mentions is set for 10x.

So if we investigate, a 72" target=6.8755 moa at 1,000 yards [72"/(1.047 *10)]@1000 yards.

The values are then doubled at 5x, 1 mil=6.8755 moa. At 5x, the target should read 2 mils for a 500 yard range.

So, we know we can take the formula, 72"/(1.047*5)=13.75 MOA. At 500 yards, the mils read 6.8755 moa each, therefore two are 13.75 moa, just as the formula predicts.

by the way good work, just wished I understood it easily.
AceSn1per

#### Stormrider

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One MOA (minute of angle) is equal to 1.047 inches at 100 yards.

#### kristian55

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1MOA - 100 yards - in.1,047 - sm.2,659

1MOA - 100 yards - in.1,047 - sm.2,659
200 yards -in.2,094 - sm.5,319
300 yards -in.3,141 - sm.7,979
400 yards -in.4,188 - sm.10,639
500 yards -in.5,235 - sm.13,299

#### sscoyote

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My 1st post here. I love applying reticles for rangefinding and downrange zeroing. As u mention multi-stadia reticle subtensions in the 2nd focal plane are inversely proportional to magnification (assuming the power ring is calibrated properly). This is great stuff and fun to play with, IMO.

Interestingly a lot of guys think that the mil-ranging formula was designed for the mil-dot, but it's actually the opposite, since the mil-ranging formula is just the simple geometric formula that defines angular systems of measurement. Here it is in it's most basic form (inches to yds.)--

tgt. size (") x range of reticle subtension (usually 100 yds.) / subtension (") / quantity of gap tgt. occupies (decimal equivalent) = range (yds.)

The whole kicker here is the subtension variable. Instead of using the milliradian 3.6" measurement, a shooter can use any reticle subtension, from simple plex to Ballistic Plex to archery sight pins. Any 2 points can be applied just like a mil-dot for rangefinding oftentimes even more accurate than the milliradian itself, if the subtension is smaller.

In fact, the "mil-ranging formula" above actually defines reticle and turret compensation for downrange zeroing as well, since if u think about it a bullet drop measurement is really the same dimension as a tgt. size.

IMO, if a shooter completely understands the inversely proportional relationship of 2nd FP subtension vs. magnification, and the most basic form of the mil-ranging formula, he'll have all he needs to know for scope reticle and turret applications.

#### llajumpvid

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Am I doing this correctly?

I have a 4-16 power mil dot scope. 8x is the power that the mil is sized for. I want to use the zoom to estimate distance for an 18" object.

So at 8x an 18" object will read 1 mil at 500yds
1.047*5=5.235"=1MOA
18/5.235"=3.438moa

If scope at 6x 8/6=1.333
500/1.33=375yd
@375yd 18" is 18/(1.047*3.75)=4.58moa
4.58/1.333=3.438moa=1 mil
375/6=62.5

If scope at 10x 8/10=0.8
500/0.8=625yd
@625yd 18" is 18//(1.047*6.25)=2.75moa
2.75moa/.8=3.438moa=1mil
625/10=62.5

So If I zoom an 18" object to fit into 1 mil spacing and read the magnification multiply by 62.5 (60 for simple math) I would get the approximate distance?

#### LibertyOptics

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So who needs FFP? :lol:

If my math is correct, then would about 1.25 mils accomplish the same thing? Find your "6 foot" target, dial until the target fits in about 1.25 mils, and then multiply the mag reading by 100??

Scott

#### fillmore

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It's a lot easier ( for me ) if the scope is calb. for the mils to read correctly
at 10x. I like to range 18" targets because that fits the chest size of
whitetail bucks more or less AND it's the height of an empty Bush Lite
18 pack box,lol.
If you bracket the target w/ 1mil divide the power setting by 2 gives
yards to target ( in hundreds)

or

If you bracket the target w/ 2mil divide the power setting by 4 gives
yards to target ( in hundreds )

#### Iceking007

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I need to sign up for a university coarse to learn how to use a scope, Flying an air plane is simple in comparison, gone are the days of lining up the crosshairs on the 22 and pulling the trigger when you where 10.

Ill never learn this stuff!

#### Iceking007

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I need to sign up for a university coarse to learn how to use a scope, Flying an air plane is simple in comparison, gone are the days of lining up the crosshairs on the 22 and pulling the trigger when you where 10.

Ill never learn this stuff!

#### mele

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it just takes a little experience... it is not as bad as it sounds

MEL

#### gsmithplm

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It may be that I am mis-remembering this but... I think some older ranging devices used a similar principle. Increase the magnification till a known height object fit between horizontal two lines and read the result off the dial. Golf flags come to mind.

#### rsimpson

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Where is the eat place to begin when trying to learn these principles? I'm totally lost reading these numbers but I don't have Amy of the foundational knowledge, either... Is there any book, website, or thread that can explain (in great detail and simplicity) the basics of using and calculating MOA and Mils? Thanks!

Ryan

#### Studley2436

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Hi all, this is my first post here but I have been ghosting for a while. I am a hunter interested in longer range shooting. One of the things I like about shooting is the maths. I think I might be able to fill in a couple of things for people.

The radian is a unit of measure. It has been around longer than I know about and is in fact the preferred way for scientists and mathematicians to measure angle. (Using an XL spreadsheet to do any work with angles you must use radians. I suppose because scientists made it up.) It is based on the formula for the circumference of a circle 2*pi*r. For the calculation r or radius is always 1. One mile, or one meter or one inch or one anything it does not matter. This means the distance around the circle is 2*pi. One milli radian is one thousandth of this. The other important thing is that in degrees you are measuring angle but in radians you are measuring the distance around the circumference of the circle.

The important thing to do with your scope is to find out what magnification will have the mildots reading as true. It is at max magnification on my Sightron S111 and is not marked, but is marked and a bit less than max on my Monarch scope. If the scale is true at 16x power then going to 8x power means that one mil read on the scale is equal to 2 mils for your calculation. 4x power will make it 4 mils and 2x power makes it 8 mils. Each time you halve the power you have to double the mils.

Here is the bit you have all been waiting for the calculation.
Object size(Inches)X27.77/mil dot reading = distance in yards
If you are converting to meters Object size(inches)X25.4/mil dot reading = distance in metres.
If you want to avoid remembering the conversion factor
Target size (in yards) x 1000 / Mils read = yards to target
or in metric
Target size (in metres) x 1000 / Mils read = meters to target
Easiest one of all to remember if you want maximum simplicity and can handle metric
Target size(in millimetres) / Mils read = meters to target you can change this answer to yards by multiplying by 1.1

I hope that helps

Steve

#### electricman4759

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Great stuff Studley2436,

If anyone still does not understand this you can check the link below from Cheaper Than Dirt and it may help. This link is all about range estimation and it also gives you a chart to go by, and that takes all the math out.

http://www.cheaperthandirt.com/MediaPag ... diaid=1106

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