GTA
Support Equipment For PCP/HPA/CO2 and springers ,rams => Optics, Range estimation & related subjects => Topic started by: Fowlpursuit on September 12, 2014, 09:06:21 AM
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Got a utg 3-12x44 mil dot scope. What I'm wanting to do is make a chart of distances according to the mils a target takes up. In other words I'm using a 4" target size (width of a squirrel/height of a starling) and in 10 yrd increments 20-100 yrds how many mills will this target measure?
Standard formula= distance unknown
My needed formula= mil-measurement unknown
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Got a utg 3-12x44 mil dot scope. What I'm wanting to do is make a chart of distances according to the mils a target takes up. In other words I'm using a 4" target size (width of a squirrel/height of a starling) and in 10 yrd increments 20-100 yrds how many mills will this target measure?
Standard formula= distance unknown
My needed formula= mil-measurement unknown
If you can use meters to target, calculated by known height or width of target in centimeters?
Goes like this: 1 mil= 1cm @ 10 meters, so 1 mil = 2cm @ 20 meters, 1 mil = 5cm @ 50 meters, see the progression. Formula centimeters counted(milled) between center to center of two mildots, multiplied by 10 equals meters to target. eXample (target is 4 centimeters tall) you count 4 centimeters between 2 mildots on your reticle, multiply by 10, your firing solution is 40 meters range to target.
Actually all you have to do is place a zero, beside the centimeters milled! :P
You can practice in this simulation: http://www.shooterready.com/ (http://www.shooterready.com/) Just be sure to use the range card calculated in meters, of course you can practice using yards, but my method only works metric. ;)
The .1mil FFP scope is my favorite and what I practice with in the "Is the shooter Ready?" simulation. ;D
The white part of the silhouette is 101.5cm.
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I just did this for my browning Leverage in.177.
With AA diablo Fields I found at ten yards the gun shoots two full mil dots low . Then between 15-20 feet it begins to hit one mil dot down. At twenty five feet it begins hitting the crosshairs. Then it is centered on the crosshairs out to forty five feet. Then after that it is one mil dot down.
I set up every five feet and moved the target back and forth. Your gun pellet even the grade of the ground will change things.
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A RULER viewed at 100 feet with scope at an accurate 12X will view 1 mil dot per inch.
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A RULER viewed at 100 feet with scope at an accurate 12X will view 1 mil dot per inch.
Are you saying 1 mil = 1 inch @ 100 feet ? Should that be the same with a 10x mil dot reticle?
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A RULER viewed at 100 feet with scope at an accurate 12X will view 1 mil dot per inch.
Are you saying 1 mil = 1 inch @ 100 feet ? Should that be the same with a 10x mil dot reticle?
Yes ... based on a scope having 10X mil-dot calibration
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I believe the utg operates. On a "metric" or mils system.. Vs. an MOA.. And it states mils read true at 10x... Will this ruler thing work even tho the mils are based on a metric scale?
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I believe the utg operates. On a "metric" or mils system.. Vs. an MOA.. And it states mils read true at 10x... Will this ruler thing work even tho the mils are based on a metric scale?
Mils are neither metric(meters) or English (yards). You can have mil or moa reticles, just for some reason scopes with turrets mismatched to the reticle are the standard. Moa turrets with a mildot reticle, typical. You can find scopes with matched turrets and reticles. Although it's expensive to find scopes with moa turrets matched to moa reticles they're out there.
Milliradians explained: http://www.firearmsadvantage.com/milliradians_explained.html using mils and geometry you can calculate distance to an object.
BTW The hard part is converting mils to moa's to yards, although it's very very easy converting mils to meters. :) :) :) :P
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Guys,
Have you tried the Chairgun Program? It provides you an inch of drop/etc. table that is very useful. Also can be set up to run on various Magnifications, calibers,speeds, and pellet combos.
It splits your screen display and also provides an indicator (cool graph) for all of you Mildots. The "Killzone" feature is very good. Of course any of the calcs/programs have to be field verified, but good stuff to learn from.
Perhaps it'll help to visualize and make your "own" chart that you can use... most guys make one. Look at the turret, and you'll see how it adjusts @ the yardage. The metric conversion is already done for you. ie 3.6"@ 100yds/1.8"@50yds, etc. It's old stuff.
Anyway, no matter what make scope you buy, this program is worth your time. It's free and worth a few hours:
http://www.hawkeoptics.com/chairgun.html#.Ud7Ah6xBFiw (http://www.hawkeoptics.com/chairgun.html#.Ud7Ah6xBFiw)
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Guys,
Have you tried the Chairgun Program? It provides you an inch of drop/etc. table that is very useful. Also can be set up to run on various Magnifications, calibers,speeds, and pellet combos.
It splits your screen display and also provides an indicator (cool graph) for all of you Mildots. Of course any of the calcs/programs have to be field verified, but good stuff.
Perhaps it'll help to visualize and make your "own" chart that you can use... most guys make one. Look at the turret, and you'll see how it adjusts @ the yardage. The metric conversion is already done for you. ie 3.6"@ 100yds/1.8"@50yds, etc. It's old stuff.
Anyway, no matter what make scope you buy, this program is worth your time. It's free and worth a few hours:
http://www.hawkeoptics.com/chairgun.html#.Ud7Ah6xBFiw (http://www.hawkeoptics.com/chairgun.html#.Ud7Ah6xBFiw)
How can I put that computer program into my rifle scope? ::) Good luck doing all that math in your head while holding the sight picture in your rifle scope!
BTW a better approach would be to use ballistic calculator app with and Iphone, least you can keep it with you where it's needed.
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You make your own 3x5 card "shooter card". Most guys do it, when they get their specific rifle/bullet/pellet dialed in. Even little circle card inserted in you're "flip up" cover, to "remind" you Dot/yardage Afield. You'll get it.
Nothing new there.
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I guess it's hard to grasp new concepts, you can teach an old dog new tricks......or can you???? I memorize drop and reticle range find inside the scope. Loosing the sight picture to look at a range card, (the old way) usually gives target time to getaway as in a real world environment. A laptop on the bench is another thing altogether! ;)
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I'm assuming that you have a very good amount of time, and understanding of your rifle/ammo combo. Before you get out there. I'm an old hunter and FT player.
So you're dead on right... no need to use Iphone, or whatever, once you get afield.
The info I give is very instructional, and easy to write down...
LOL! Us olders, (or Multi gun owners), don't remember everything we ONCE did...BUT give us a "hint", and
We'll surprise you! :D
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I'm assuming that you have a very good amount of time, and understanding of your rifle/ammo combo. Before you get out there. I'm an old hunter and FT player.
So you're dead on right... no need to use Iphone, or whatever, once you get afield.
The info I give is very instructional, and easy to write down...
LOL! Us olders, (or Multi gun owners), don't remember everything we ONCE did...BUT give us a "hint", and
We'll surprise you! :D
Nothing you do surprises me ::)
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So there is no yard/meters difference in a mil-dot? Only the way I covert the target size either inches or meters dictates the way my target is ranged?
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So there is no yard/meters difference in a mil-dot? Only the way I covert the target size either inches or meters dictates the way my target is ranged?
Mildots are in miliradian, so are neither yards or meters. The difference is in the math used to reticle range find being simple for metric or complicated for yards. Yes, using English or metric target dimension's determinds the math required.
http://www.firearmsadvantage.com/milliradians_explained.html (http://www.firearmsadvantage.com/milliradians_explained.html)
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The Mildot system is set up for 10x magnification. In inches, these are the center to center distances at various yardage. We'll use a Std 3.6" disc, and view it at the ranges:
C/C Dot Size How the Image Looks to you
100yds = 3.6" It'll fill just 1 dot space, center to center.
50yds = 1.8" half the 100 yd - so it'll take 2 dot spaces, instead of just one space
25yds = 0.9" 1/4 of the 100 yd - so it'll take 4 dot spaces, instead of just one space
10yds = 0.36" 1/10th of the 100 yd - It's gonna be pretty darn big to look at ! ;)
This will get you started, and you'll learn to interpolate the halfway stuff with practice. Hope this helps some.
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I agree with Built and Condor. Making some useful points and pointing in the right direction.
Jay
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Well obviously I'm screwing something up here. I used 5" and converted it to yards multiplied by 1000 (A) I then took that and divided it by the number of yards I desired to shoot at. My hope was this would give me the mil-dot measurement.. Some how tho it does not work when I put my calculations to the test in the field..
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You lost me converting 5in to yards multiplying times 1000? I'd convert 5in to cm's which is about 12.5cm. Count cm's covered by 1 mil, place zero beside cm's milled for meters ranged to target. Choose drop hold. execute firing solution. ;D
I recommend iPhone app or laser rangefinder or minimum programmable calculator.
You could work up a standard drop chart using the mil-dots for holdover/under aimpoints with a rangefinder. Using the rangefinder first and then using aimpoints to complete your firing solution.
IMHO you're making things way too complicated. ( for me. ) Just my 2 ¢'s
If you can draw up a formula, I'm sure someone with mathematical skills can " HELP " as I have none?
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Bo doubt I am making thing complicated- my situation is this- I have a benjiman NPXL 1100. Decided to up grade to the utg 3-12x44 scope and GRT III trigger. Scope is here and still waiting on trigger. Small game season opens today. I realize I'm going to have to spend some Time on the range but don't wanna spend any more time then I have to. I already have tradjectory info for 14.3gr round nose pellets. 10-100 yrds. My hope was to figure out wat a 5" target measures in mils from 10-100 yrds and figure out ness nessacary hold over in relation to my already known tradectories using the math formula. Then I could just do a sight in and confirm my calculations at the range allowing me more time in the feild..
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Ok. Maybe this is necessary. Set 5in target @ each known distance/known drop, take mil reading of 5in target @ each known and document onto your drop chart. The mils measured will change with magnification, so use the exact magnification you zeroed at or even this won't work! As I said I have no math skills. You should do this after the math anyhow to prove the math. ???
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Yes this is precisely what I will end up doing.(I did the same with the provided centerpoint)Was just hoping to make the math work /just a personall accomplishment I guess and something to take up my time while I wait on the trigger to get here as I wanna do my sighting in wit it installed
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Need Chairgun help!
Can I add parameters of target size and target distance, just to look at the sight picture/reticle, to accurately see exactly where the mil-dots lay on the target. Would the simulation be exactly same as using the real world target's sight picture?
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Bo doubt I am making thing complicated- my situation is this- I have a benjiman NPXL 1100. Decided to up grade to the utg 3-12x44 scope and GRT III trigger. Scope is here and still waiting on trigger. Small game season opens today. I realize I'm going to have to spend some Time on the range but don't wanna spend any more time then I have to. I already have tradjectory info for 14.3gr round nose pellets. 10-100 yrds. My hope was to figure out wat a 5" target measures in mils from 10-100 yrds and figure out ness nessacary hold over in relation to my already known tradectories using the math formula. Then I could just do a sight in and confirm my calculations at the range allowing me more time in the feild..
If you're still having problems, feel free to contact me via P.M. here on the GTA. I'll help.
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Fowlpursuit, if you go to leapers site for that product download the mil dot PDF they have giving size and mill readings..
however with variable power scopes like 3-12 and having the mil set standard at 10x power you will never be 100% spot on without a stop in place at exactly 10x. With mil dot reticle and MOA turrets a mildot master may be helpful as well. (SWFA has them I think)
Condor22 also pointed out using a known target size at different yards/meters to get the readings on different magnifications (KISS). If this is a second focal plane reticle be sure the POI stays the same at each distance. Some scopes don't hold it changing magnification if they are SFP in stead of FFP.
Hope this is helpful information and Happy Hunting!
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http://www.mil-dot.com/media/1027/the_derivation_of_the_range_estimation_equations.pdf (http://www.mil-dot.com/media/1027/the_derivation_of_the_range_estimation_equations.pdf)
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I just joined here, and don't know if I should resurrect this thread, but optics applications for long-range shooting and rangefinding is one of my passions. My system for reticle-rangefinding in the field is like this (hypothetical measurements)--
mils-range--
3.0-75
2.5-100
etc.
this way it can be easily referenced in the field when placed in a Butler Creek scope cap cover.
Now when it comes to subtension (reticle) systems for rangefinding (not just mil-dot) the math is as follows (inches to yards)--
tgt. size (") x range of reticle subtension measurement (yds.) / reticle subtension (") / "mil reading" (decimal equivalent) = range (yds.)
looks complicated but very easy to apply, so for your 4" tgt size using the milliradian subtension here's the 1st, say 50-yd. calc--
4 x 100 / 3.6 / X = 50
X=2.2 mils
so your 1st entry is--
2.2-50
now it should be easily seen that 4 x 100/3.6 =111.1 (what I refer to as the tgt/subtension factor), so now the calcs become much faster--
111.1/X=60
1.9=60 (2nd entry)
etc. to as far as the reticle allows you to go efficiently
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Now, here's another interesting (and very useful) thing to know about reticles in 2nd focal plane scopes--reticle subtension is ~inversely proportional to magnification. That means that if the subtension between like areas between dots (center to center, like edge to like edge), is 3.6" @ 100 yds. @ 10X, then at 12X it'll be 10/12 = X/3.6, X=3.0" @ 100 yds.
Now crank the scope to the optic's highest power (the reticle subtension "stop" as Kristoff mentions above), and you should be at 3.0 " @ 100 yds.
Now use the same formula above and replace the 3.6" subtension variable in the equation with 3.0" and recalc everything. Now you have a more accurate and more precise system of reticle rangefinding.
Yes...it's true that magnification is often slightly different than what's marked on the power ring, but everyone I've ever checked is as calculated.
In my experience 2 very important concepts that should be understood is--
1) The "mil-ranging" formula defines rangefinding (as well as downrange zeroing) with any multi-stadia reticle and tgt. turret.
2) Reticle subtension is ~inversely proportional to magnification in 2nd FP optics.
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Many hours ago , someone suggested " Use Chairgun "
What a wonderful bit of advice that was .
I have a Ballistics chart for all my Airguns , all derived from Chairgun. Its a cool program to play with and the more familiar you use it the more information you will get from it .
Dont try to re-invent the wheel ,
Dare to go There !!!
Supaflee
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Now, here's another interesting (and very useful) thing to know about reticles in 2nd focal plane scopes--reticle subtension is ~inversely proportional to magnification. That means that if the subtension between like areas between dots (center to center, like edge to like edge), is 3.6" @ 100 yds. @ 10X, then at 12X it'll be 10/12 = X/3.6, X=3.0" @ 100 yds.
Now crank the scope to the optic's highest power (the reticle subtension "stop" as Kristoff mentions above), and you should be at 3.0 " @ 100 yds.
Now use the same formula above and replace the 3.6" subtension variable in the equation with 3.0" and recalc everything. Now you have a more accurate and more precise system of reticle rangefinding.
Yes...it's true that magnification is often slightly different than what's marked on the power ring, but everyone I've ever checked is as calculated.
In my experience 2 very important concepts that should be understood is--
1) The "mil-ranging" formula defines rangefinding (as well as downrange zeroing) with any multi-stadia reticle and tgt. turret.
2) Reticle subtension is ~inversely proportional to magnification in 2nd FP optics.
Take your 3.0" subtension one step further. Airgun distances are relatively close. If you work in feet rather than yards, it become 1" subtensions. The math then become easy enough to do in your head (I still use charts to speed things up).
At SFP 12X:
A 1" target, spanning 1 dot space, is 100' away.
A 1" target, spanning 2 dot spaces, is 50' away.
etc.
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I see it Scott...it all comes down to units--
inches x yds./inches = yds.
or
inches x ft./inches = ft.
Have often been fascinated by the math, and have seen some impressive things happen by using and manipulating it.
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If you look at feet conversion and inch subtentions, you can "trim everything down" to airgun users.
12/10x....9/10x....6/10x etc is really easy with a calculator.
Just use 10x as your basis, and remember that at 10x is the MILDOT standard:
The MILDOT 10x standard Center to Center from the Crosshair zero is:
Center to Center @ 100yds, 1Midot= 3.6" @50 yds, 1Mildot=1.8" @25yds, 1Mildot=7/8"
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If you look at feet conversion and inch subtentions, you can "trim everything down" to airgun users.
12/10x....9/10x....6/10x etc is really easy with a calculator.
Just use 10x as your basis, and remember that at 10x is the MILDOT standard:
The MILDOT 10x standard Center to Center from the Crosshair zero is:
Center to Center @ 100yds, 1Midot= 3.6" @50 yds, 1Mildot=1.8" @25yds, 1Mildot=7/8"
A standard mil-dot (usualy at 10x) is a milliradian which is 1/1000 of a radian. So:
At 1000 yards, each dot spans 1 yard.
At 1000 inches, each dot spans 1 inch.
At 1000 meters, each dot spans 1 meter.
That is the basis for it all. Don't mix units and there is NO conversion factor. Or, mix the units and magnification any way that you want, but just use the appropriate scale factors.
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I've seen some amazing things accomplished with the "mil-ranging formula" in it's most basic form. Understanding the formula completely allows it to be applied for more than just the mil-dot reticle. It can be used with any 2 points at one distance relative to any 2 points at any other distance. I've used it with iron sites, and even archery sight pins for rangefinding and it also defines downrange zeroing as well, since a bullet or pellet drop at any distance is the same type of dimension as a target size.
The 2 best things about the mil-ranging formula is that it's easily memorized, and it's adaptable to more than one application.
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If,
Range (yards) = {size (yards) * 1000}/mils
and size = 4 inches = .111 yards,
then
Range (yards) = {.111 * 1000}/mils = 111/mils
and
***range/111 = mils***
It is very easy to set this up in a spread sheet and have it crank out the range, size, mils, whatever you like for hundreds of values. For things like this Xcel or whatever Libre office or Open office calls it is your friend.