Advanced Marksmanship My Mil formula for distance in yards

[xrob]

I'm just a hobby shooter that enjoys shooting at distance
This is a Formula for range finding unknown distance targets that I use.

I need my distance in yards for my ballistic calculator so I use this. Just curious what the more experienced guys think about it.

I find it rather easy and quick with a calculator and I don't have to mess with decimals and meter conversions.

target size in inches x 100 / subtension / mils = distance to target in yards

ex.
18" target x 100 / 3.6 / .5 = 1000 yards

 

[_Windrider_]

I'm just a hobby shooter that enjoys shooting at distance
This is a Formula for range finding unknown distance targets that I use.

I need my distance in yards for my ballistic calculator so I use this. Just curious what the more experienced guys think about it.

I find it rather easy and quick with a calculator and I don't have to mess with decimals and meter conversions.

target size in inches x 100 / subtension / mils = distance to target in yards

ex.
18" target x 100 / 3.6 / .5 = 1000 yards

Seems to work. I checked it on my Mil Dot app and it agreed.

 

[Nick_or_Rutledge]

I'm just a hobby shooter that enjoys shooting at distance
This is a Formula for range finding unknown distance targets that I use.

I need my distance in yards for my ballistic calculator so I use this. Just curious what the more experienced guys think about it.

I find it rather easy and quick with a calculator and I don't have to mess with decimals and meter conversions.

target size in inches x 100 / subtension / mils = distance to target in yards

ex.
18" target x 100 / 3.6 / .5 = 1000 yards

Well, the derivation is as such.

1 milliradian 1/1000 radians

Size of target in inches = T
Size of target in mils = M
Range to target in inches = R
Range to target in yards = Y

tan(M*.001) = T/R

due to small angle (tan(x) = x)

M*.001 = T/R

R = T/M*.001

R is in inches Y = R*1/36

36Y = T/M*.001

Y = T/M*.036 = T*27.78/M



This is almost the same as yours, but your equation is written in steps and is not quite right as it is. It should be more like [(Target*100)/3.6]/size in mils=distance

That being said, as long as you do it in that order and don't try to rearrange the equation it works.

 

[goodgorilla]

what is subtension?

 

[Rob01]

I'm just a hobby shooter that enjoys shooting at distance
This is a Formula for range finding unknown distance targets that I use.

I need my distance in yards for my ballistic calculator so I use this. Just curious what the more experienced guys think about it.

I find it rather easy and quick with a calculator and I don't have to mess with decimals and meter conversions.

target size in inches x 100 / subtension / mils = distance to target in yards

ex.
18" target x 100 / 3.6 / .5 = 1000 yards

Why reinvent the wheel? Why not just use the yards mil formula of:
Target size in inches x 27.78 / size of target in mils = range in yards

Or even easier, get a Mildot Master.

 

[Lowlight]

That would be too easy Rob... cause there isn't a host of formulas out there already, LOL

 

[Jaeger308]

Come on Rob it is: Target size in inches x 27.77777777777777 / size of target in Mils = Range in yards.

Use what works for you however keeping it simple is key.

 

[Exo]

im personally a fan of the yards / mils variant

SOT (yards) * 1000 / MIL = Range
18" example --> .5 * 1000 / .5 = 1000

 

[Rob01]

Yeah easy examples rarely come up in actual use and having to convert inches to yards to use that formula is a pain in the ass.

Sorry Kurt. I hate 7s.

 

[Jedi]

Yep that about sums it up
Work smarter NOT harder

 

[M40_A1]

A mil-dot master is a great tool, and as any tool it can fail or get misplaced or lost. And, if it does, you'll wish you had worked harder at being smart.

 

[Nick_or_Rutledge]

A mil-dot master is a great tool, and as any tool it can fail or get misplaced or lost. And, if it does, you'll wish you had worked harder at being smart.

I like to integrate a mil-dot master into my drop cards for this reason. If you lose your dope you are hosed anyway.

This is a pic of one of my drop cards:



To use it:
Pick a target that is 6", 18" or 36" (or some value between that is easy to interpolate)
Mil it
Compare to chart value and find corresponding yardage

(i.e. find 6" target and mil it. If it were .3 mils then it is at 550 yards.)

 

[Rob01]

A mil-dot master is a great tool, and as any tool it can fail or get misplaced or lost. And, if it does, you'll wish you had worked harder at being smart.

You are smart if you have redundant systems to take care of the problem at hand in case one is lost. If you lose multiple redundant systems and have to end up doing something in your head then you are just incompetent and would probably be better off bowling.

 

[xrob]

Why reinvent the wheel? Why not just use the yards mil formula of:
Target size in inches x 27.78 / size of target in mils = range in yards

Or even easier, get a Mildot Master.

Don't you think it is easier to do the math in your head / scratch paper with the lower numbers of 3.6 and whatever mil reading you get?

Ex.

12" target

(1200/3.6)/1 = 333

VS

12(27.78) / 1 = 333


As for a mil dot master, I need to get one for sure.

 

[Rob01]

Don't you think it is easier to do the math in your head / scratch paper with the lower numbers of 3.6 and whatever mil reading you get?

Ex.

12" target

(1200/3.6)/1 = 333

VS

12(27.78) / 1 = 333


As for a mil dot master, I need to get one for sure.

If it comes to the point where you are having to do mil formulas in your head or even on paper then you have come to the point where it would be quicker and more efficient to look at the target, guess the range and send a round out and correct. Doing math in your head under time and/or pressure is a recipe for failure.

This is why I carry the following with me at matches. First off a laser range finder as it's ultimately faster and more accurate than using the reticle. But always having a back up to electronics, there is a mildot master dummy corded to my belt. 3 sets of preset mil target sizes and readings, similar to pic below, laminated and placed in my rifle stock pack, pack and dummy corded to my belt. A small solar powered calculator on my belt and usually another in my pack. I also have my rifle data taped to the rifle, laminated and dummy corded to my belt and another in my pack. I like the old saying that preparation is the mother of all success.

 

[Lowlight]

If you are doing MATH in the field you've already lost... don't care what the math is for, ranging, wind, elevation... if you trying to find the easiest formula to do on the fly it's called NONE.

Prior Proper Planning prevents Piss Poor Performances.

 

[Darkside-Six]

Don't you think it is easier to do the math in your head / scratch paper with the lower numbers of 3.6 and whatever mil reading you get?

Ex.

12" target

(1200/3.6)/1 = 333

VS

12(27.78) / 1 = 333


As for a mil dot master, I need to get one for sure.

sure that works, but what happens when the target is much larger. have you ever tried that on a 4ft high silhouette target? multiplying 4800 x 3.6 gets to be a real pain in the ass. Dope your own rifle, make your own cheat cards, have a MD master as back up.

 

[Scottimus]

I am also a hobbiest long distance shooter and recently started practicing using my mildot master. My initial experience was a significant disparity in distance when determining range with the mildot master vs my Burris Eliminator laser range finder.
Eg: I ranged a standard stop sign (30" across) the mildot master indicated it was 600 +/- yards out, the laser rangefinder said 720 yards. Tried several other targets at varied distances with varied results. I think the biggest issue / variable is taking the time to get really accurate measurement in mils. Thoughts?



Sent from my iPad using Tapatalk

 

[Exo]

Scottimus, ranging via mil or moa initially is frustration. The biggest thing that helped me was shooterready.com ... the demo's there helped me put into perspective what exactly 2.3, 2.4, 4.1, etc etc MILs look like. Once you get a good idea how BIG the target is (in the reticle) its just simple math.

 

[M40_A1]

Also, a mil reticle in a higher magnification is helpful, as long as it is on a steady platform. Mil reticles with 2/10 subdivisions help, too.

 

[Rob01]

I think the biggest issue / variable is taking the time to get really accurate measurement in mils. Thoughts?

That's exactly it. You need to practice breaking the reticle down into at least .1 mils accurately and with some reticles getting down to .05 mils is fairly easy with practice.

 

[Johan L.]

My Mil formula for distance in yards

Why reinvent the wheel? Why not just use the yards mil formula of:
Target size in inches x 27.78 / size of target in mils = range in yards

Or even easier, get a Mildot Master.

Why not use target size in yards?

Target size in yards / size of targets in mils x 1000 = range in yards

And the answer is?.......somebody messed up the relationship between inches and yards.

And the solution is?.......the metric system!!

Target size in meters / size of targets in mils x 1000 = range in meters.

1 meter is 100 cm or 1000 mm or 10 dm. There you have it. Keep it simple....

 

[Rob01]

Because rarely are target sizes given or come in exact yards or meters so you have to convert an inch measurement to a fraction of a yard and then do that formula. Adds another step.

Also in the US most ranges and people use yards as a range. Not meters.

 

[-R-]

Math makes my head hurt, I like to keep it simple. Simple = fast.

 

[riffraff]

Rob01 --

Any chance you could email me the file on that chart of yours?....it makes lots of sense. Check your PMs for email address....free beer for you whenever we are at the same event!

Cheers

Buzz