• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

benchmstr

Sergeant
Full Member
Minuteman
Oct 10, 2007
1,332
1,207
CEO Team waffle house
i have never did the equation for wind freehand...just with exbal...can someone give me a equation to figure out wind, given i know the windspeed?

bench
 
Re: reading wind?

Different calibers will differ. Even the same caliber out of different guns or with different velocities, bullets or loads will all be different. What are you shooting?
 
Re: reading wind?

Here's a pretty simple formula I use for fast calculations:

<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
(range in yards/100) * wind (mph)
wind hold(mils) = ----------------------------------
constant
</pre></div></div>

The constants I use are:

<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
Range(yards) Constant
<= 500 45
600 43
700 41
800 39
900 38
1000 37
</pre></div></div>

However, that's a rough approximation for my load. If you want one more accurate, use a ballistic program set up for your load and a 1 mph full-value crosswind, and work the formula backwards:

<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
(range in yards/100) * wind (mph)
constant = ----------------------------------
wind hold(mils)
</pre></div></div>

But you can use a ballistics program and Excel to build a windcard like this one, which you can quickly use in the field to calculate the effects of varying wind - the wind holds are in mils:

windchart.jpg

 
Re: reading wind?

Good to combine the equations too bench. Lindy has the best shorthand equation for mil hold. Don't get confused by a few other equations out there just because you see the constants are different. Be sure to look for the conversion you are wanting...MOA or Mil. With A LOT of practice, you will get fairly consistent at calling wind without Exbal. Not to say you won't want to pull your hair after a miss, but you will at least be able to learn from it. LOL Good luck.