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# MilDot Calculations and zoom

#1
06-05-2009, 07:22 AM
 Bronze Member Join Date: Jul 2008 Posts: 40
MilDot Calculations and zoom

I have been using a MilDot reticle with a reasonable degree of success, but due to my eyesight not being as good as it could, have tried an alternaive method.
On my scope, the MilDot is accurate at 10 power only. At 500 yards, 1 Mil measures 18"(as we all know). If I increase the zoom power to 19 (10 - 40 x 50mm), then that 18"on my target covers 2Mils. So, as the range increases, if I use that zoom increase with the appropriate calculations, will I still find the measurement of range just as accurate as if left at 10 power?
My reason for asking is that over 500 yards, smaller animals such as Australian foxes are a bit hard to see well enough to accurately gauge the range. Zooming in will make a big difference.

Last edited by peterb; 06-05-2009 at 07:26 AM.. Reason: extra information
#2
06-05-2009, 09:32 AM
 Bronze Member Join Date: Apr 2009 Location: Holland, MI Posts: 76
Re: MilDot Calculations and zoom

Yes....if you use your power is to 10x as new mil measurement is to one mil.

IE...if you're using 20x....you cut your distance measure in half.

This is just all learned from using the mildot in "Long Range Shooting Simulator"
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#3
06-05-2009, 07:09 PM
 Bronze Member Join Date: Jul 2008 Posts: 40
Re: MilDot Calculations and zoom

Thanks.
I was "shooting in" a scope at 100 yd increments out to 1000yds, but was having problems seeing the target centre (home made) at the further ranges, so drew a couple of lines on the side of the target 18" apart and then started fiddling with the zoom. It appeared to work reasonably well when matched to the rangefinder, but as if often said : " If it's too good to be true, it generally is ", so I thought I would ask the question.
#4
06-06-2009, 09:32 AM
 Bronze Member Join Date: Apr 2009 Location: Holland, MI Posts: 76
Re: MilDot Calculations and zoom

I'm still working on it......anything past 800 yards gets iffy for me.
__________________
ΜΟΛΩΝ ΛΑΒΕ

Aim small hit small

When they come for your guns, give them the ammunition first.
#5
06-06-2009, 11:59 AM
 Silver Member Join Date: Feb 2009 Location: Truckee Posts: 293
Re: MilDot Calculations and zoom

This wouldn't be a problem if the reticle was in the first focal plane.

I'm currently trying out the horus vision scope with its awesome reticle and front focal plane.
#6
06-06-2009, 12:40 PM
 Junior Member Join Date: Jun 2009 Posts: 12
Re: MilDot Calculations and zoom

The Horus Reticle system or any First Focal Plane (FFP) is awesome for ranging if you are doing the calculations, even better for quick corrected shots. I've got one of there H37 reticles and the only thing that works against this system IMO is that the thickness of the hash marks increases proportionally with magnification (they are super-fine lines to start with, so it's really not much of an issue) which is the oposite of a second focal plane scope that is common. With the FFP the hash mark increaments don't change the measurement no matter what the magnification. I think what peter was noting was that he doesn't need to make much of a calulation because the proportional change in magnification is equal to that of the range. It's a smart solution for his problem. If you are willing to make some very simple calculations, I have to back theodore with the Horus system. It's simply phenomenal.
#7
06-06-2009, 09:26 PM
 Gold Member Join Date: Oct 2007 Location: Patagonia Mountains, Arizona Posts: 742
Re: MilDot Calculations and zoom

PeterB:
Since your scope is 10-40x and reads in mils (milliradians) at 10x it will read exactly in inches per dot spacing at 100 yards if you set it at 36x magnification. You then simply estimate the number of inches the portion of the object you're looking at is high or wide between any two adjacent dots. That number is the distance to the object in hundreds of yards. That works well for people used to thinking in inches and yards. For people who are used to the metric system Mils are easier.

The limit on accuracy is only how accurately you can judge the physical size of the objects. That's why I use laser rangefinders instead.

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