Mil Dot Scopes?

skunx123

skunx123

New member
Hey got a couple questions about mil-dot style scopes.

first is that i have read that mil-dot scopes are only accurate on their highest magnification,

has anyone used variable power mil-dot scopes at different magnification for accurate range readings?

thanks for any help.
 
Originally Posted By: skunx123Hey got a couple questions about mil-dot style scopes.

first is that i have read that mil-dot scopes are only accurate on their highest magnification,

has anyone used variable power mil-dot scopes at different magnification for accurate range readings?

thanks for any help.

I have the same question, you beat me to it. LOL


Mark2
 
Depends if it is first focal plane or second. If it is second it is max power most of the time. Hince when your are using milldots. FFP adjust with power.
 
First focal will let you range at any magnification. Second focal will need to be set at the range magnification. The set range magnification is usually at the max or is sometimes set by a dot or mark on the magnification knob. If your constantly ranging i would recommend a FFP scope. If you wanna range for fun, get a SFP scope. Just my recommendation.

Jake
 
O, it also makes it easier if you have matching turrets with the mil dot. You see your shot you just dial it up or hold using the mil dot. Its really easy to get the hang of. I've converted from MOA scopes to MIL scopes.

Jake
 
A mil-dot scope changes it's subtension just like any other 2nd focal plane reticle would. I use my 6-18x Nikon Buckmasters MD scope at 18 (instead of the mil-cald. power of 12) for rangefinding and windage applications. At 18x it's 66.7% (12/18) of 3.6 or 2.4 inch per hundred yds. between dots (from 1 point on a dot to the same point on the next dot). The dot subtension itself is also 66.7% of mil-cald. or basically a ~1/2 IPHY dot instead of a ~3/4 IPHY dot (better for prairie dogs, IMO). Nice thing about the 2FP mil-dot is that the dot is still .2 of the dot to dot subtension no matter what power you're at.

A lot of guys are using the Center Point 4-16x mil-dot that is actually cald. for 10x (3.6 IPHY between dots), even though there is no witness mark on the power ring.
 
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Originally Posted By: sscoyoteA mil-dot scope changes it's subtension just like any other 2nd focal plane reticle would. I use my 6-18x Nikon Buckmasters MD scope at 18 (instead of the mil-cald. power of 12) for rangefinding and windage applications. At 18x it's 66.7% (12/18) of 3.6 or 2.4 inch per hundred yds. between dots. The dot subtension itself is also 66.7% of mil-cald. or basically a ~1/2 IPHY dot instead of a ~3/4 IPHY dot (better for prairie dogs, IMO). Nice thing about the 2FP mil-dot is that the dot is still .2 of the dot to dot subtension no matter what power you're at.

A lot of guys are using the Center Point 4-16x mil-dot that is actually cald. for 10x (3.6 IPHY between dots), even though there is no witness mark on the power ring.


Yeah, what he said. Lol

How many years does it take to know all of this technical stuff. Thanks for the education on scopes.

Mark2
 
Pretty sure that mildot rangeing is calibrated to be most accurate at 10 power.
 
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How many years does it take to know all of this technical stuff. Thanks for the education on scopes.

Mark2 [/quote]


Mark--it took me a couple years before i figured this stuff out since it wasn't as commonly understood as it now is, and i had to learn it mostly on my own. You would not beleive the misinformation there was out there regarding turret and reticle math...and still is for that matter.

Took me a couple weeks to figure out that the mil-ranging formula isn't specific to the mil-dot, and can be used with any 2 points at 1 distance relative to any 2 points at another distance.

Then it took me a couple months to completely understand the 5 variables in the formula and to be able to manipulate them to calculate any one of the variables once the others were known (reverse milling basically).

It took me a couple days to figure out that subtension is inversely proportional to magnification in a variable-powered 2 focal plane scope. Figured that 1 out right out the window of my old house on signs of various dimensions at various distances with a plex-reticled scope.

Then it was a study in the math behind rangefinding with a multi-stadia BDC-style reticle whose subtensions don't repeat (Ballistic Plex, Varmint Hunter, etc.).

Then it was a couple years before i figured out that the mil-ranging formula also defines bullet drop relative to a scope reticle or turrets too.

Then it took a few years to learn to subtract 1 line thickness with line reticles for the most accurate system of rangefinding when using them (don't tell the guys at snipershide that though--the mgt. there doesn't agree). Actually stumbled upon this a few years ago while reticle-ranging a buck antelope using the Ballistic Plex reticle.
 
Originally Posted By: sscoyote At 18x it's 66.7% (12/18) of 3.6 or 2.4 inch per hundred yds. between dots.

Steve, don't mean to nitpick, as I know how well versed you are in this stuff. But, for the benefit of those learning, don't you mean 2.4" from center to center of the mildots? The distance subtending between the dots will alway be less in relation to the full mil value (center to center)and dependant on what size the mildots are...

Good shootin'
Fred

EDIT:
To further clarify:

Given a .2mil sized mildot & scope set at proper ranging power, the distance between the dots will be .8mil, or 2.88" @ 100yds. (3.6 x 0.8)

 
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Jon, on the OpticZone is very correct about different manufacturers using different points for the calibration of their Mil-Dot scopes...
Quote:Sightron usually have theirs on high power My Sightron was the first Mil-Dot I had ever had any experience using and when I called the Customer Service at Sightron, they told me that my 4-16x should be used at the 16x for mil-dot ranging...(They also sent me a three page instruction sheet for the mil-dots)

I now have three mil-dot scopes and the other two are calibrated at 10x..and I found that information hidden in the instructions furnished with the scope..

If it's not in your instructions with the scope, it may be worth your while to call the manufacturer for clarification...Most of them want you to have a good experience with their scope so you will tell the next guy..
 
Yeah Fred that's correct--thanks on that 1. Here's the best representation on how the system works for the old Army std. .2 mil-dots that most companies are using these days--


USArmyMildotreticle.gif


Now suppose you're looking at a 10" steel plate at an unknown distance through my 6-18 Ninon Bckmstrs. scope set at 12x where the subtension between dots measures 3.6 inch per 100 yds. (on centers), and i fits perfectly between inside dot edges (.8 mil). Here's the equation--

10x100/3.6/.8=347 yds.

Now crank the scope up to 18 and look at the same plate FROM A DIFFERENT location, and it occuspies the same .8 mil. Remember the subtension is now 2.4 IPHY between dots on centers--

10x100/2.4/0.8=521 yds.

Suppose u measured the Simmons 3-9x plex-reticled scope, x-hair to plex post tip now and it measures 3.7 inches at 58 yds. (@9x). You're using your old el cheapo scope here on your big game rig because u can't afford 2 mil-dot scopes--the good MD optic is on your coyote rig. U look at your 15" back to brisket antelope buck on a foggy day when the lasers not working (you just crawled out of a ravine after making a long stalk), and u see that he occupies ~.9 x-hair to plex post tip. Here's the equation--

15x58/3.7/.9=260 yds.

See how it works?
 
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There is an aid that will help the learning curve for learning how to use a mil-dot reticle, It's called "Mil-dot Master". You can go their website and order it.


Chupa
 
My vortex 6x24x50 mils at 14 and my 4200 ffp is at any power.Don't think your going to use these on predators on the move ,the only way there used is to mil objects of known dimensions before hand.A 30" target at 1 mil is 833yrds ,a 33" target at 1 mil is 916yrds and that's if you mil it right exact.You can mil areas and adjust your turrets.
 
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