Wind Calculation

[2brothers641]

I started dabbling in longer range shooting with my CZ .22 lr. I am using Strelok Pro for my ballistics app and ran into some issues for my wind holds. My shooting distances were: 30, 50, 100, 150, 175.

At 30, there was virtually no wind, 50 very little, and 100+ 15-20 mph. This was mostly due to natural wind block along the shooting lane.

How is everyone dealing with this situation? Is there any baseline calculations to get on target faster or how do you compensate for wind drift for only a portion of the bullets flight?

Thanks for any insight.

 

[6.5SH]

I started dabbling in longer range shooting with my CZ .22 lr. I am using Strelok Pro for my ballistics app and ran into some issues for my wind holds. My shooting distances were: 30, 50, 100, 150, 175.

At 30, there was virtually no wind, 50 very little, and 100+ 15-20 mph. This was mostly due to natural wind block along the shooting lane.

How is everyone dealing with this situation? Is there any baseline calculations to get on target faster or how do you compensate for wind drift for only a portion of the bullets flight?

Thanks for any insight.

For non-uniform winds the only modern phone apps I've seen with wind zones are Trasol and the now defunct Genesis.
For PC, and also the engine behind both apps is Patagonia's ColdBore.

The usual method is observation of the miss and adjusting off of that while trying to shoot the same wind condition.

While a program can certainly apply some math to the estimates, I've not seen a good simple rule of thumb like @Jack Master wind rose for applying wind for different zones.

Looking forward to more experienced replies on this.

 

[Jack Master]

I started dabbling in longer range shooting with my CZ .22 lr. I am using Strelok Pro for my ballistics app and ran into some issues for my wind holds. My shooting distances were: 30, 50, 100, 150, 175.

At 30, there was virtually no wind, 50 very little, and 100+ 15-20 mph. This was mostly due to natural wind block along the shooting lane.

How is everyone dealing with this situation? Is there any baseline calculations to get on target faster or how do you compensate for wind drift for only a portion of the bullets flight?

Thanks for any insight.

Dope the wind for the distance the bullet is in that wind condition. Take the yardage out of the wind call that is in the "no wind zone"

making your conditions listed above more simple
0-75yds = no wind due to wind break = 0 wind hold
75 yards to target at 150 yards = same wind hold as target at 75 yards with the same cross wind.

75yard target with crosswind = 1.2 mils <-- target at 150 yard with zero wind from 0-75 yds and wind from 75-150yds = 1.2 mils. Can you see how these are the same wind hold and condition?

Here is a diagram showing the 2 conditions. You'll see the wind drift for both situations are the same.

At most ranges I take the full crosswind speed and dope the wind to the full target distance. (for this example it was 2.5 mils) Then I start to look a the terrain and see if there are places the wind is not present. In this example the wind is only effecting the bullet for the second 1/2 of the flight distance so I would use 1/2 the wind call (1.2)
If the wind break is at the 2nd half of the flight path and the wind is full value for the first half, I would use 3/4 of the wind call. (1.9mils) This is because the bullet will have an initial lateral movement/momentum when it enters the no wind section of flight. The wind deflection in the area will be liner rather than exponential.

 

[2brothers641]

Great info. Thank you!

 

[Conaso]

Dope the wind for the distance the bullet is in that wind condition. Take the yardage out of the wind call that is in the "no wind zone"

making your conditions listed above more simple
0-75yds = no wind due to wind break = 0 wind hold
75 yards to target at 150 yards = same wind hold as target at 75 yards with the same cross wind.

75yard target with crosswind = 1.2 mils <-- target at 150 yard with zero wind from 0-75 yds and wind from 75-150yds = 1.2 mils. Can you see how these are the same wind hold and condition?

Here is a diagram showing the 2 conditions. You'll see the wind drift for both situations are the same.

View attachment 7845382

At most ranges I take the full crosswind speed and dope the wind to the full target distance. (for this example it was 2.5 mils) Then I start to look a the terrain and see if there are places the wind is not present. In this example the wind is only effecting the bullet for the second 1/2 of the flight distance so I would use 1/2 the wind call (1.2)
If the wind break is at the 2nd half of the flight path and the wind is full value for the first half, I would use 3/4 of the wind call. (1.9mils) This is because the bullet will have an initial lateral movement/momentum when it enters the no wind section of flight. The wind deflection in the area will be liner rather than exponential.

Is it that simplistic?

https://appliedballisticsllc.com/wp-content/uploads/2021/06/Where-does-wind-matter.pdf

Based upon the OP's comments, I'm guessing 0-50 no wind, 50-100 3mph (very little), and 15mph 100-175. So, it's not 50/50, but three wind segments of 0mph (56%), 3mph (32%), and 12mph (12%) = .3mils. Someone would have to use Trasol to see how close my swag.

 

[6.5SH]

Is it that simplistic?

https://appliedballisticsllc.com/wp-content/uploads/2021/06/Where-does-wind-matter.pdf

Based upon the OP's comments, I'm guessing 0-50 no wind, 50-100 3mph (very little), and 15mph 100-175. So, it's not 50/50, but three wind segments of 0mph (56%), 3mph (32%), and 12mph (12%) = .3mils. Someone would have to use Trasol to see how close my swag.

Interestingly Trasol is the only one that lets you edit the wind zones to such short ranges, neither ColdBore or Genesis will (and all 3 the same engine).
Using 1070 fps and .130 G1 your mph+ranges end up at .6 mils in Trasol.
Using @Jack Master 1/2 the distance and 1/2 the wind call resulted in 1.1 mil or .55 mil half value for 15 mph @ 75 yards.
His method seems to be pretty spot on.

 

[Conaso]

Dope the wind for the distance the bullet is in that wind condition. Take the yardage out of the wind call that is in the "no wind zone"

making your conditions listed above more simple
0-75yds = no wind due to wind break = 0 wind hold
75 yards to target at 150 yards = same wind hold as target at 75 yards with the same cross wind.

75yard target with crosswind = 1.2 mils <-- target at 150 yard with zero wind from 0-75 yds and wind from 75-150yds = 1.2 mils. Can you see how these are the same wind hold and condition?

Here is a diagram showing the 2 conditions. You'll see the wind drift for both situations are the same.

View attachment 7845382

At most ranges I take the full crosswind speed and dope the wind to the full target distance. (for this example it was 2.5 mils) Then I start to look a the terrain and see if there are places the wind is not present. In this example the wind is only effecting the bullet for the second 1/2 of the flight distance so I would use 1/2 the wind call (1.2)
If the wind break is at the 2nd half of the flight path and the wind is full value for the first half, I would use 3/4 of the wind call. (1.9mils) This is because the bullet will have an initial lateral movement/momentum when it enters the no wind section of flight. The wind deflection in the area will be liner rather than exponential.

O.K., now I understand. But what if there is wind before the barrier, then the barrier, and finally wind again after the barrier but at the same or a different velocity? If someone can point me to a book I can purchase that explains the different scenarios I would be most appreciative.