Charts from The Wind Book for Rifle Shooters

[RHux]

When using a Wind Value Conversion Chart , how do you generate a Windage Chart for a specific load. The ones provided in the book had to be generated somehow. I use the book provided one for 308, now I need one for 140gr 313 g7 BC 6.5 bullet at 3150.

 

[memilanuk]

Which page?

 

[RHux]

The wind value conversion chart is on pg 49 figure 44. It is used with a windage chart like the one on pg 124 figure 85

 

[RHux]

http://bulletin.accurateshooter.com/2013/10/good-resource-the-wind-book-for-rifle-shooters/

 

[Dusty Stevens]

Triggertime with your exact combo is the best book. Let the wind change and shoot- make a note of where it goes. No book will show you where your rifle will hit

 

[284winner]

Triggertime with your exact combo is the best book. Let the wind change and shoot- make a note of where it goes. No book will show you where your rifle will hit

That is the best way to get the precise dope of any cartridge for either drop or windage. Sure helps tho if you have a minute of wind number to start with rather than burning ammo for the exact numbers. I use the calculator for that purpose and fine tune till I get exact numbers. The difference is, drop won't change ( at same distance range) until elevation or temp changes. Windage does to some degree with each shot when wind is present. Wind is the biggest obstacle to defeat. As stated by Dusty, the only real defense is to shoot in it.

 

[suasponte]

https://play.google.com/store/apps/details?id=com.borisov.strelokpro

Ballistic calculator, and chronograph your load.
Also, as stated shooting with a stated purpose rather then just aiming and pulling the trigger.
Note the wind on your face, look at the mirage, take a picture of it in your mind when you pull the trigger, and finally calling your shot impact. It helps a bunch to have somebody in a pit pull your target and mark it. Nothing better then saying a "X" at 12 and have the target come up with the spotter there.

 

[suasponte]

Here is a couple screen shots from my phone with Strelok. Dasher load. 600yd with 10mph full value wind. All my load data and the dope for it at the bottom. Note 11.5MOA come up for the 600yd target. Next is the reticle veiw, note target distance is called out as 600yd and there are purple values above the hash marks, those are the wind values for those hash marks. Example: far right and left hash marks are 20mph hold offs for that load at 600yds. Also note at the top of the screen, you can dial your come up (11.5 moa) and the target will move vertically in your reticle to the proper elevation. Also the target is placed for a 10mph point of impact. So, you can build a data sheet for your hold offs (if that is your style of shooting). Before you ever pull the trigger. However, confirmation on paper is a must. Hope this helps.

 

[243Mendoza]

When using a Wind Value Conversion Chart , how do you generate a Windage Chart for a specific load. The ones provided in the book had to be generated somehow. I use the book provided one for 308, now I need one for 140gr 313 g7 BC 6.5 bullet at 3150.

Use chrono for velocity, JBM for wind/moa at different yards, trig for angles other than 90 deg and excel for generation of wind chart table. An the attachment is an example excel file.

 

[memilanuk]

Use chrono for velocity, JBM for wind/moa at different yards, trig for angles other than 90 deg and excel for generation of wind chart table. An the attachment is an example excel file.

^ this. Pretty much what I do if I want a printable wind chart or 'rosette'. Although if you're lazy and/or scared off by the 'trig', you can play with the wind angles in JBM to generate the values you want to put in the chart. Probably faster/easier/less error prone to do it via formulas, though.

 

[243Mendoza]

^ this. Pretty much what I do if I want a printable wind chart or 'rosette'. Although if you're lazy and/or scared off by the 'trig', you can play with the wind angles in JBM to generate the values you want to put in the chart. Probably faster/easier/less error prone to do it via formulas, though.

Yes, there is an error in my chart for 90deg but it was rush job!

 

[RHux]

Thank guys that was exactly what I was looking for

 

[RHux]

It's just the sin of the angle. Basically you're just looking for the component of the wind perpendicular to your bullet path which you find by sin(angle). Cos(angle) will give you the component of the wind that is parallel to your bullet path but you don't really care about that probably.

sin(90) = 1
sin(60) = (sqrt 3)/2 = 0.86602540378443864676372317075294
sin(45) = (sqrt 2)/2 = 0.70710678118654752440084436210485
sin(30) = 0.5

Using that you can make a chart as precise as you feel like. In the field though you probably couldn't distinguish an angle that accurate so the 90,60,45, and 30 one is pretty good.