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Rifle Scopes Need Help Ranging With Scope! Please Help!

E

EasternNChunter

Sergeant
Full Member
Minuteman
Aug 28, 2012
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Eastern NC
I have a match Saturday and one of the stages will be using your scope to range 5-6 different targets at unknown distances. I have a FFP Steiner 5-25x56 G2 Mil Dot scope. I also have Shooter on my phone. You can use anything (calculator, apps, etc.) but a rangefinder. Last time I used Kentucky Windage and was close enough to get points but I want to figure this out. Any help would be appreciated greatly. Thanks!
 
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Ok I'll make this as easy as possible. First thing you need to know is the size of your target. You want to know the size of your target in YARDS!!!

So if you're shooting at an 18" target then you do 18/36 = 0.5 yards
lets do some more examples:
30" = .833 yards
20" = .555 yards
15" = .416 yards
So if I haven't made this clear you need to know the size of your target in YARDS! I'll admit there are other ways to do this but this is fast and easy to understand.

Ok hopefully that's clear.

Ok now that you've got your target height in yards multiply that number by 1000.

So our examples again:
18" = 500
30" = 833
20" = 555
15" = 416

So far the only math you've done is to convert your target size to yards. (Hopefully you will know your target sizes before hand and you can convert them to yards before hand).

Ok now that you have this number measure the target in your scope and try to get an answer at least to the nearest tenth mil. Then divide that number into your value from above.

So your target is 18 inches and it reads 1.2 mils tall in your scope. 18" is .5 yards so 500/1.2 = 416 yards.
So your target is 20 inches and it reads 1.6 mils tall in your scope. 30" is .833 yards so 833/1.6 = 520 yards
So your target is 15 inches and it reads 3 mils in your scope. 15" is .416 yards and 416/3 = 138 yards
So your target is 20 inches and reads 2.3 mils in your scope. 20" is .555 yards and 555/2.3 = 241 yards

Clear as mud?

If you have any further questions fire away.

~Brett
 
As stated, you have to know the height of your target. If you don't know the height, or they won't let you measure it (I always have a sewing kit type fold-able measuring tape in my misc. stuff pouch) then you should do some homework on known objects in the very close vicinity of your target. For example the target stand its in if its a paper target, the actual cardboard they used if its a standard size, a stop sign thats right near it, etc. Don't know where you are shooting, so not sure how many other points of reference you'll be able to see.

Anyways, use your mildot and get a mildot master as well. Learn the sub-tensions of your reticule. If you don't, even if you know the target height you will probably be off as the calculation below will be wrong.

27.78 x target height in inches = X

X / mils in your scope = distance to target in yards

Using an example above: So your target is 20 inches and reads 2.3 mils in your scope. 20" is .555 yards and 555/2.3 = 241 yards

27.78 x 20 = 555.6

555.6 / 2.3 = 241.565

Here's a more detailed explanation:

8541 Tactical - Mildot Range Estimation
 
I doubt he'll have a woman purse with him (a reticule). I'd recommend that he should use his reticle as he'll probably actually have one of those. ;) Really wish people would stop calling them reticules. Drop the U!

~Brett
 
There really is no need to remember the 27.78. Granted the 27.78 is correct if you want to use target size in inches. However why remember it? Everyone knows already that there are 36 inches in a yard. Then all you need to remember is:

(size of target * 1000) / size of target in scope = range

Then all you need to know is that the units you use for the size of the target are the units you get in the range. So if you input the target size in meters then you get the range in meters. If you input the size of the target in inches then you can get the target range in inches. You can use whatever you want and the same equation ALWAYS works. I'm a game for trying to remember as little as possible and when I do commit to remembering something I want to remember the most useful bits possible. That is why I like the equation as above. Its always useful and it works no matter what you know about the size of the target. The only thing you then need to know is how to get the size of the target into the units that you want your range in. If you get the target size in micro furlongs then you have a problem. But if you get it in inches then you should already know how to get that to yards. If you're given the size of the target in meters then a rule of thumb can be to add about 9.5%.

~Brett

PS: 1000/36 = 27.78 (thats where it comes from)
 
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Exactly as long as you have the calculator it really doesn't matter. More often I'm working with similar sized targets. At one match that I've been to all the targets are 10" x 16". I use the 16" height and I know that its .444 yards. Thus I only remember the 444. Now all I need to do is read the size in my scope and divide it into 444. Takes a lot fewer pokes on the calculator, easier to remember, and less prone to error.

The other piece is that you start to learn the inch to yard values real quick and they start to stick in your head.

1" = 27
2" = 55
3" = 83
4" = 111
5" = 138
6" = 166
7" = 194
8" = 222
9" = 250
10" = 277
11" = 305
12" = 333
13" = 361
14" = 388
15" = 416
16" = 444
17" = 472
18" = 500
19" = 527
20" = 555

And its not too often you get to shoot at targets bigger than that at a match. If you wanted this could be put onto a card and store it with your ballistic table.

~Brett
 
If you need to work in meters (I tend to):

Target height (inches) X 25.4
------------------------------ = Range in Meters
Height in Mils
 
Wouldn't any self respecting meter shooter rather know the size of their target in centimeters?

~Brett
 
bh-ltr said:
Wouldn't any self respecting meter shooter rather know the size of their target in centimeters?

~Brett
Click to expand...


Just for you: :)

Target (in cm) X 10
---------------------= Range in Meters
Height in Mils


(To get cm from inches multiply x 2.54)

I'm too American to think in cm, so I use inches, but maps (and the military) work in meters, so I sort of split the difference.
It makes sense to the voices in my head.
 
Ok, the math has gotten a fairly good treatment above. What has not, and in my experience the source for most error, is the act of measuring the target size (subtension). This is the hard part and depending on target size, range, and caliber can introduce a lot of error. EasternNChuter, what you need to do is pick a math procedure that makes sense to you (understanding is key) and start measuring things with your RETICLE. (no F*&KING U!) I have found that on typical target sizes the difference between 0.75 mils and 0.80 mils can be a miss. Esp. with slower calibers (.308). Precise measurement of subtension through the scope is a perishable skill, and needs to be practiced. My advice to your original query, is to always try to measure down to the hundredth (to the half tenth anyway). Below is a brief proof of the importance of precision in the UKD scenario. Have fun at the shoot, wish I could join you!


target size = 18" --> 18/36=0.5

Subtension measured = 0.80 mils
Then later refined to = 0.75 mils

Range 1 --> 0.5/0.80=625yds (just move the decimal)
Range 2 --> 0.5/0.75=667yds

Normal .308win 175gr SMK ballistics; (elev only)
625yds = 5.0mils or 111.7"
667yds = 5.5mils or 131.9"

Note that if you do everything right except pay attention to a "half tenth", a shot at a reasonable size target is a total miss!
 
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Couldn't agree more with the importance of PRECISELY milling the target. Thanks for getting us back on track (and I was out of Math).
 
bogeybrown said:
Just for you: :)

Target (in cm) X 10
---------------------= Range in Meters
Height in Mils


(To get cm from inches multiply x 2.54)

I'm too American to think in cm, so I use inches, but maps (and the military) work in meters, so I sort of split the difference.
It makes sense to the voices in my head.
Click to expand...

Thus why all the europeans love the metric system. So nice and clean as long as you stay within it. I can't say I've run into someone using target size in inches and range in meters. Actually I don't know a lot of shooters who use meters. Know a good split of mil vs moa people but most think in yards. All the meter people that I've known consider the inch about as useful as a beard second.

~Brett
 
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bogeybrown said:
Target (in cm) X 10
---------------------= Range in Meters
Height in Mils
Click to expand...

Just to be technical, the above would get you range in decimeters. multiply by 100. This is why one should move beyond the decimal point and understand the operation not just use a formula by rote.
 
The primary factors are (to me):

1: Have the most accurate target size you can

2: Be able to accurately read your reticle to ensure the most precise measurement you can get.

3: KNOW the math

4: Practice!!!

The more time you spend behind the reticle the better. That being said, feel free to use this ShooterReady for a little desktop practice. Side note...it may be just me, but the windage seems to be fubar on the demo. But the milling is pretty good.
 
Know to use your reticle properly. Use the outside of your reticle and put the last mil worth of the target into the vernier area so that you can get a finer gradation for the most accurate possible mil value.

~Brett
 
While it is good to know the formulas as a back up...OP stated he has Shooter, which has a distance calculator. Might be wise to figure out how it works.
 
I'm slydexic so numbers and dowrs always get turned around. I use the distance calculator in Shooter to do the calcs. In Shooter with the ammo selected, go to the distance entry (first entry on the list) hit the 3 dots (option menu) and the left hand side is "Calculated distance". Enter target size in inches, feet, Yrds, cm, or meters and the size in Mils, IPHY or MOA. Shooter will automatically populate the distance with the correct range to target then hit the solution. Make sure you have "Operation mode" set to advanced under preferences and "save atmosphere" checked and you should be GTG. Good Luck on the match.
 
Is there a time limit?
Do you have to shoot the targets?
Will you be given the size of the target?
Do you know the maximum and minimum distances?
 
If you can use "Shooter" then you should be able to use "Ballistic" a simuliar program

The Ballistic program has a "rangefinder". Just put in the size of the target in inches via sliding the bar at the top. Then on the left is a mil scale (also MOA). Just look at the "know size target" then at the target in the MIL Dot scope in the program. When looking through your scope you'll see the target is covered by X number of MIL. Slide the bar on the Ballistic programs to make it look like what you see in the scope. You get the distance read out.

Really simple, no math, just visual, pretty quick too, but like every thing else you need to know the size of the target OR the distance of an unknown size target.

This puppy is pretty quick to use.
 
1. Learn to break down your reticle to atlast .1 mil. With practice .05 mils is possible.

2. Learn to break down your reticle to atlast .1 mil. With practice .05 mils is possible.

3. Get a mildot master and use it.

4. Learn to use the inch formula as every target I have ever been asked to range in any comp over the past 10 years has been given in inches and never in yards. The yard formula requires you to convert inches to yards to use it. The 27.78 formula and a calculator is easy but a mildot master is much easier and faster.
 
bh-ltr said:
I doubt he'll have a woman purse with him (a reticule). I'd recommend that he should use his reticle as he'll probably actually have one of those. ;) Really wish people would stop calling them reticules. Drop the U!

~Brett
Click to expand...

Hey hey, what I choose to bring shooting with me is my business!

I blame spell check.
 
Rob01 said:
Learn to use the inch formula as every target I have ever been asked to range in any comp over the past 10 years has been given in inches and never in yards. The yard formula requires you to convert inches to yards to use it. The 27.78 formula and a calculator is easy but a mildot master is much easier and faster.
Click to expand...

^^ exactly, never have been given or used target size in yards in any match, always inches. There are also many ballistic programs that have range estimators. I use Knights Bullet Flight and it has a mildot range estimation calculator in the app, so even if you don't know or remember 27.78 you have the solution at your fingertips.
 
I know you're going to get the target height in inches. Thats why I said take that value and divide by 36 to get it in yards then multiply by 1000 and divide by subtension. Once you understand that you're dividing by 36 to get it into yards and then using the same equation no matter what its easier to remember than 27.78.
 
No it's not. It's making the process more complicated than is needed by doing extra math. 27.78 is not hard to remember and if you need to then write it in your data book if its not in there already or on a piece of tape on the back of your calculator. I know Impact Data Books come with a full page with all the equations needed. But again a mildot master is easier and faster.
 
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First there was 9mm vs 45

Then there was bolt vs semi

Then later came MOA vs MIL

Now theres yards vs inches

Great. Just great.
 
Is it easier/more accurate to do this on higher or lower powers? Should I be on 25x for all ranges? I understand being a FFP scope it won't "matter" but what is usually easiest to use? Are all of these app programs (Shooter) using height instead of width? Asking because all of my given reticle subtensions are given as widths. I am assuming they are the same as the heights. Thanks again fellas.
 
I'll weigh in again on the inches / yds thing. I'd like to reiterate however that what works for YOU is the right way. Now...

The difference between multiplying by a constant (27.78) or dividing by a constant (36) is exactly that... either you use the x on the calc or you use the /. Arguing about which is better is silly. The real issue that folks get all worked up is the little dot (decimal). When you multiply inches by 27.78 you get yards multiplied by 1000. If you multiplied inches by 0.02778 you'd get yards. By 2.778, yards times 100. Divide by 0.036, or 36, or 0.36, or even 36,000, go ahead, try it. You get the same answer, the difference is the order of magnitude. And if you can't or wont see that the target is 345 yds away instead of the 34.5 or 3450 yds that your calculator says, you've got bigger problems. Multiplying or dividing by any number that begins with 1 and is either followed or preceded by one or more 0's only moves the decimal, 2nd grade math. Folks who include any multiplying or dividing by 1000 in the formula they use don't understand the math they are using. You all can argue forever about the operations and constants you choose to use (ie works for YOU) but the math is all the same.

One more opinion from me on this topic, then I'll get off my soapbox. The Mil-dot master is a fine tool, but it doesn't provide the precision needed if your target is small or the subtension is not a multiple of 0.25 or smaller than 1.0. There have been a few folks (not just me) that counsel precise measurement, to the 0.05 mil if possible, and the MDM just doesn't easily allow for it. I have one, I've used it, but I find that I'm more accurate and precise if I use a calculator and the method I outlined in post #14. As always YMMV.


-------------
Edit; Yea, it's generally easier to get a precise subtension on higher powers. But clarity of image becomes an issue sometimes too. (mirage) So use the power that allows the clearest and then biggest view of the thing you're measuring. I have backed off power just so I could see the edges without so much mirage.

Height, width, length, distance between... Any dimension as long as it's perpendicular to the line of sight.
 
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EasternNChuter;

Just to be extra clear, you could stand on your head and use the horizontal stadia line to measure a diagonal distance from the corner of a door to a light socket, enter it into your calculator as "hight" and get the correct range as long as the physical distance and subtension were measured accurately. (maybe that wasn't more clearerer...):p
 
It's ok Kirk. You could out-shoot me with a straw and a napkin. Does that make us even?
 
EasternNChunter said:
Is it easier/more accurate to do this on higher or lower powers? Should I be on 25x for all ranges? I understand being a FFP scope it won't "matter" but what is usually easiest to use? Are all of these app programs (Shooter) using height instead of width? Asking because all of my given reticle subtensions are given as widths. I am assuming they are the same as the heights. Thanks again fellas.
Click to expand...

Depends; the more you go over 10x the more mirage will get you. There are times where at above 15x I can't see the target for shit because the mirage is making it look like its dancing around.

Aim small, miss small.
 
EasternNChunter said:
Is it easier/more accurate to do this on higher or lower powers? Should I be on 25x for all ranges? I understand being a FFP scope it won't "matter" but what is usually easiest to use? Are all of these app programs (Shooter) using height instead of width? Asking because all of my given reticle subtensions are given as widths. I am assuming they are the same as the heights. Thanks again fellas.
Click to expand...

Bro, just PRACTICE!!!!!. You are WAY over-thinking this process, and most of us have been really happy to help you over-think it. You have the formulas, you have an optics-equipped rifle, I'm hoping you live in a structure with a window. WITHOUT FREAKING OUT YOUR NEIGHBORS, practice ranging objects outside your house. Street signs, license plates, doors, windows, soda cans, etc are standardized sizes you can reference. If I understood your first post, you HAVE a LRF, you just can't use it for this match, so use it to check your estimation skills. Play with different power settings, practice on objects at angles/obliques where you can't use height because it's not vertical so you have to use width, etc.
These formulas will melt your brain on a computer screen. When you're laying behind your rifle with a calculator, MDM, Shooter, or whatever else you use, it will make sense, and you will SEE how wrong an estimate is because you didn't break down your reticle subtensions far enough. I think you'll find that one of these formulas will make more sense than the others and will be your go-to.
Now go forth grasshopper and TRAIN!!!!!!!!!!!!!!!
 
bogeybrown said:
....You are WAY over-thinking this process, and most of us have been really happy to help you over-think it....
Click to expand...


Holy hell yes! Thank you. I'm officially unsubscribing from this thread. Thanks for the question Eastern, have fun, be safe... I'M OUT!
 
pinsandpitons said:
I'll weigh in again on the inches / yds thing. I'd like to reiterate however that what works for YOU is the right way. Now...

The difference between multiplying by a constant (27.78) or dividing by a constant (36) is exactly that... either you use the x on the calc or you use the /. Arguing about which is better is silly. The real issue that folks get all worked up over is the little dot (decimal). When you multiply inches by 27.78 you get yards multiplied by 1000. If you multiplied inches by 0.02778 you'd get yards. By 2.778, yards times 100. Divide by 0.036, or 36, or 0.36, or even 36,000, go ahead, try it. You get the same answer, the difference is the order of magnitude. And if you can't or wont see that the target is 345 yds away instead of the 34.5 or 3450 yds that your calculator says, you've got bigger problems. Multiplying or dividing by any number that begins with 1 and is either followed or preceded by one or more 0's only moves the decimal, 2nd grade math. You all can argue forever about the operations and constants you choose to use (ie works for YOU) but the math is all the same.

One more opinion from me on this topic, then I'll get off my soapbox. The Mil-dot master is a fine tool, but it doesn't provide the precision needed if your target is small or the subtension is not a multiple of 0.25 or smaller than 1.0. There have been a few folks (not just me) that counsel precise measurement, to the 0.05 mil if possible, and the MDM just doesn't easily allow for it. I have one, I've used it, but I find that I'm more accurate and precise if I use a calculator and the method I outlined in post #14. As always YMMV.


-------------
Edit; Yea, it's generally easier to get a precise subtension on higher powers. But clarity of image becomes an issue sometimes too. (mirage) So use the power that allows the clearest and then biggest view of the thing you're measuring. I have backed off power just so I could see the edges without so much mirage.

Height, width, length, distance between... Any dimension as long as it's perpendicular to the line of sight.
Click to expand...

I agree with whatever works for you is what you should go with but I also don't like doing something that takes more time and operations like converting inches to yards and then doing the formula. What's easier?

Size in inches x 27.78 / mil size= range

Size in inches/ 36 x 1000/ mil size = range

Adding more steps makes it harder for a new shooter trying to get a grasp on the whole situation. Learning the inch formula is a better way as whether you get the target size in yards or inches, which is the way he will get them, he has the formula. I am no math wizard but what i do know is how to mil targets and how to get the range from doing so. Just trying to give the OP the easiest way for him to do it from the start.

And you are wrong on the mildot master. Up to 3 mils target size you can easily break it down to .05 mils for the mil reading. Look at the right side of the mildot master. It's right there. That size says bullet drop but it is for use with smaller targets. Try it. Line up 10" with the 1 mil mark on the left side and then look to the right. 10" is lined up with 1 mil. Alot of people don't realize the right side is used to break down to use for fine measurements. The mildot master works great and is quick and easy. No batteries to die or electronics to fry. Get it wet and it doesn't matter. It's a must in the data book cover in my opinion.

Honestly, miling targets to get ranges is very sketchy once you get past 600 yards or so and today there are much better ways like LRFs to get ranges. You should learn to do it as a back up but if another way to do it is available then use it. Breaking down the reticle is a mandatory skill IMHO as not for ranging but for holds which you will use more.

Eastern, higher power is easier as you can see better but as mentioned when mirage starts coming into the picture it really does make life harder. Try and be at the highest you can and still clearly see the target.
 
pinsandpitons said:
I'll weigh in again on the inches / yds thing. I'd like to reiterate however that what works for YOU is the right way. Now...

The difference between multiplying by a constant (27.78) or dividing by a constant (36) is exactly that... either you use the x on the calc or you use the /. Arguing about which is better is silly. The real issue that folks get all worked up is the little dot (decimal). When you multiply inches by 27.78 you get yards multiplied by 1000. If you multiplied inches by 0.02778 you'd get yards. By 2.778, yards times 100. Divide by 0.036, or 36, or 0.36, or even 36,000, go ahead, try it. You get the same answer, the difference is the order of magnitude. And if you can't or wont see that the target is 345 yds away instead of the 34.5 or 3450 yds that your calculator says, you've got bigger problems. Multiplying or dividing by any number that begins with 1 and is either followed or preceded by one or more 0's only moves the decimal, 2nd grade math. Folks who include any multiplying or dividing by 1000 in the formula they use don't understand the math they are using. You all can argue forever about the operations and constants you choose to use (ie works for YOU) but the math is all the same.

Height, width, length, distance between... Any dimension as long as it's perpendicular to the line of sight.
Click to expand...

One term - Slide Rule

:)
 
MilDot Master, get one. I started using inches instead of yards and now my brain is stuck that way. If I had started using yards then I'm sure I would be using yards. Problem in switching between the 2 is after doing enough calculations you start to just remember the solution. Calc and shoot enough times with the same gun/load and which method you choose will be inconsequential, IMHO. Everything you need to know is posted above. Nice job fellas
 
It's actually possible to obtain an interpolative accuracy level of ~.1 of 1/2 mil with those G2 mil reticles [1/2 mil subtension units]. You definitely need to study the systems if you're going to be competing in matches though. Knowledge=success...usually.
 
All this math makes my head hurt... Pick a formula and use it. Use is a lot and when you think you have used it a lot, use it again. Develop your own system and keep consistent. I have and older Springfield armory scope that had turrets that had 7.5 Moa's per rotation. That was confusing so I came up with a system and used it... a lot and it worked.
 
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