Thread: Survival books
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Old 05-27-2007, 16:46   #39
Biscuitsjam
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Join Date: Jan 2004
Posts: 6,262
Re: Books on Ranging targets?

Quote:
Originally posted by windplex
Any suggestions for a good book for ranging targets using binoculars or standard objects in the environment? (ways other than a range finder?) Thank you!
I wrote this elsewhere, so I'll repost it here:


Well, I'm not an expert on long-range shooting, and the most I've ever shot with a rifle is 300 meters. However, I did learn a few things in tank gunnery.

The best way to estimate range is to use the hash marks on your binoculars or rifle optics. These hash marks measure off 1 "mil" (milli-radian) intervals. Basically, an object one meter tall will be almost exactly 1 mil high at 1000 meters. It you know the height of your target, you can figure out the distance. If you know the distance, you can figure out the height.

Equations:
Height in meters = H
Distance in kilometers = D
Mils on your binos = M

Basic Equation:
H / D = M

To solve for distance using a known height:
H / M = D

To solve for height using a known distance:
D * M = H

Let's make it really simple and use a tall man who is exactly 2 meters tall (approximate 6'7") as your target. He would be:
1 mil at 2000 meters
2 mils at 1000 meters
4 mils at 500 meters
8 mils at 250 meters
16 mils at 125 meters

Obviously, most men aren't this tall and you won't usually know the exact height of your target, so you have to guess. Here are a few more precise numbers if you want a better estimate:

2 mils at 880 meters - Average American male
2 mils at 820 meters - Average American female (or average North Korean male)
2 mils at 1200 meters - Abrams Tank
2 mils at 940 meters - Humvee

The math is simple enough that you should be able to do it in your head, and after you do it for a while, it'll become instinctive. If you have some trouble working this out in your head, there are shortcuts. For instance, my tank commander just estimated for a 2-meter object, then adjusted to get a decent estimate (minus 10% for a somewhat tall man, minus 20% for a somewhat short woman, etc.).

This method gets you a very quick and fairly accurate estimate of the actual distance to your target. Too easy.

Last edited by Biscuitsjam; 06-12-2007 at 20:09..
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