Wind calls for targets at multiple locations from same shooting position

[ViP]

Look at the attached picture of the range. It shows 3 targets: one at 300m, one at 400m and another at 500m. The numbers between the colored lines show the degrees from the “axis” line.
If the wind blows in a constant direction, how much would it effect calculating the wind call for each target if all 3 targets were engaged from the same shooting position?

i am finding that my wind calls are off at 500m and I think it is because I am not taking into account the relative angle of the target when I engage all 3 targets from the same position. My angle in relation to the wind changes but I am just considering the direction of the wind from my initial engagement at 300m. I pan my rifle to engage the targets at 400m and 500m and I disregard the wind direction relative to those targets.
Could this be a contributing factor for the misses I am seeing at 500m? How much of angle/wind speed would require a recalculation of wind (call). Thanks.

 

[GeoJoe]

Try dropping those same targets in BallisticsARC and see what the math says for the conditions you observed. I’m interested to know if it’s similar. We force you to input wind as a directional bearing specifically to support wind calls for targets are varying azimuths.

 

[Matches Malone]

I guess the question is how much are you missing by. I personally think that with a standard cartridge like a .308 on a 66% ipsc target that a miss will ensue by just wind direction alone.

So target size

Wind direction &
Wind call accuracy per shot (wind changes in gust)

Shot accuracy

^
Contribute to hit probability. I get that 500y isn’t that far but you still lose a lot of the forgiveness you get at closer range.

 

[Steel head]

Personally I feel angle difference is not so great that I’d worry much about it especially at those distances.

Maybe figure for 500 and fudge the other two if it’s really small targets.

 

[Jack Master]

Yes. Angle of the wind makes a difference. Depending on the initial angle of the wind to the shooter a fair change could be seen. Note each target is about 15 degrees different from each other, this a 1/2 hour change on a clock system.

Example 1
A 10 mph wind is at 12 o'clock to the shooter when starting on the 300 yard target, This is no wind hold.
Transition to the 400 yard target will need a 1/4 wind hold (wind at 11:30) - 10mph x .25 = 2.5 mph (about 0.2 mil for a 6.5 creedmoor)
Transition to the 500 yard target will need a 1/2 wind hole. (wind at 11:00) - 10mph x 0.5 - 5 mph (about 0.4 Mil for a 6.5 Creedmoor)
If you don't correct for at the 500 yard target you will miss by 7 inches with a 6.5 creedmoor
If you are shooting a light 223 round your could miss by 12 or 13 inches

Example 2
A 10 mph wind is at 9 o'clock to the shooter when starting on the 300 yard target, This is a full value wind hold. (about 0.5 mil for a 6.5 creed)
Transition to the 400 yard target will need a 96% wind hold (wind at 8:30) - 10mph x 0.96 = 9.5 mph (about 0.5 mil for a 6.5 creedmoor)
Transition to the 500 yard target will need a 86% wind hole. (wind at 8:00) - 10mph x 0.86 = 8.5 mph (about 0.4 Mil for a 6.5 Creedmoor)
If you don't correct for at the 500 yard target you will be 1.8" from the center of the target with a 6.5 creedmore
If you are shooting a light 223 your could be 4-5 inches from the center of the target.

Check out some information on this thread about wind roses we like to use.

I've recently update my wind rose. See below. This wind rose turns my wind into the 90 degree true value wind for me. I've used this at a match and it worked really well. Couple this wind rose with the MPH gun method and you have a quick wind hold. Using this rose does require time and distance as it might be slower than head math, but its more accurate as well.

View attachment 7138144

 

[ViP]

Thanks for the comments. Will apply some of this information on my next range trip.

 

[GeoJoe]

Hope my comment didn’t come across as a shameless plug. We do offer this as a free feature in the BallisticsARC app. If I can help you set up your targets to look at the math, I’m happy to do so anytime. Best of luck to you.

 

[Sheldon N]

If the wind blows in a constant direction, how much would it effect calculating the wind call for each target if all 3 targets were engaged from the same shooting position?

If the wind is coming straight at you or away from you along the 400M line, it can make a ton of difference.

 

[LawnMM]

Depends where it's coming from. If it's along the axis line probably not going to change your life at those distances.

Like Sheldon said, if it's coming down the 400 in your face and switching back and forth you better be paying attention.