Range Estimation via Mils, MOA and IPHY.

There's been some recent interest in reticle based range estimation so I thought ti would be a good time to post another tutorial. We've had some good ones in the past but they disappear after a time.

Without going into a lot of history or any trig, here are a few definitions.

Mils (milliradian)and MOA (minute of angle) are both units of angular measure.

IPHY (inches per hundred yards) or SMOA (shooter's MOA) are inch based and conversions are listed below if either your reticle or target is measured in inches instead of mils, yards or MOA.

Reticle based rangefinding for rifle scopes was developed by the Marines, which was brought over from trajectory correction for crew serve weapons.

Here's a good article on history, using the reticles, the differences and discussion on Army vs Marine reticles, etc. http://www.scribd.com/doc/6360340/user-guide-for-mildot-equiped-optics

But what I'd like to show here is that no matter what reticle is in your scope, it can be used for range estimation.





Above are a couple of common reticles, one mil based, the other MOA. Below is a link to a table of conversions. All you need to know is the size of the target and what units your reticle is base in. It works better to choose and use man made objects of known size to measure with the reticle. But head sizes usually have less variation. 10" is commonly used for people. I use 2" for squirrels. But it will also work for KZ sizes, target bases or anything of a known size.

http://www.scribd.com/doc/2069052/Mil-and-Moa-Range-Formulas-for-different-Combinations




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