Effects of cross wind on elevation

[SMK1000plus]

I know there was a thread on this not long ago, but I was not able to find it by a search.

Did a little shooting yesterday at 1035y with about a 20mph wind from 9 o'clock. Along with that the shot was across a deep canyon running steep downhill from left to right. So the wind was coming down from left to right. My elevation solution wound up being almost 2 moa more than I was expecting. We have seen variations in bc from one rife to the next with a given bullet, but this one was more. Bullet flight in this shooting location is about 1000' above the ground always making it difficult to read what the wind is doing.

Let me know your thoughts or if anyone knows the previous thread on the subject post the link.

What was your latitude and your target azimuth? Bullet (cal., weight, B.C.)? Velocity? SD? ES? Environmental info (temperature, humidity, direct sun or shade, barometric pressure, etc.)? Powder used and its temp stability?

Some of these individually or all of these variables combined, could easily account for the difference in calculated and actual firing solutions at 1,035 yards. From the terrain you described, just the direction and velocity of the wind at max ordinate could easily account for the difference.

 

[Hatrick]

Can't find that app. Whats it look like?

 

[Ckgworks]

Tagging in....it looks like this!
https://www.google.com/url?sa=t&sou...BMAB6BAgJEAI&usg=AOvVaw0cPK3Dnmnbdp7x8Sk7lJHi

 

[Ckgworks]

Double tap.....

 

[Hatrick]

Thank You CK.

 

[Capt RB]

Which when I ran the numbers thru the AB app was exactly the difference it spit out.... When left to right = 1 MOA lower. wind right to left = 1 MOA higher.
The app does not account for down drafts though. Sounds like the wind had a down draft that pushed the bullet even lower?

Opposite Right to left the bullet climbs and left to right the bullet is pushed down.
I feel the biggest advantage to 4dof for smeone new to apps is correcting your dope to actual drops. You have a known in velocity and a semi known in bc(If it is in the library it is a Doppler drag curve) you just shoot and correct the form factor and it matches up.
I have made first round hits at 1100 with my 308(I've missed 3 2nd round hits though) shooting in what is a -2100ft DA with a solid 150gn bullet. Ive struggled with other apps for first round hits beyond my dope with this.
This is a 12" plate. My phone's weather data is used in the app so once I have a load the standard is set and corrects for DA through the gps function and the current weather at the phone.
The more you play with the app to understand it the better. You need to find another reason why you screwed up the shot and it looks more and more like it's you

 

[Jim See]

In my training classes 5 years ago we started shooting targets east and west with a south wind at 1000 yards on a range from a single firing position. Minus the effect of Coriolis on the elevation we came up with a solution for the cartridges we use in prs. (6mm and 6.5 with 7.5 to 8.5 twist barells, 9-10 twist 308) The general rule of thumb I discovered and use is; for every Mil of wind I hold or dial, change the elevation solution 10%. So right to left wind holding 3 mils of wind, lower elevation .3 mils. It does not matter the distance or wind speed just adjust according to the wind correction needed. This is not perfect but it typically keeps you on a 1-2 moa target every time. Aero jump is what takes place as the bullet leaves the muzzle in a crosswind (by theory) and Magnus effect is the accumulation of an elevation change as a bullet travels down range. (basically Bernoulli effect, in that it is continual lift)

 

[Barrelnut]

When left to right = 1 MOA lower. wind right to left = 1 MOA higher.

Opposite Right to left the bullet climbs and left to right the bullet is pushed down.

Dat what I said!

 

[RockyMtnMT]

Given the terrain the wind pretty much has no choice but to run with the slope. We are basically shooting in the shadow or the highest peak of the mountain also at the same 9 o'clock position of the wind. Hoping to have a chance to shoot this same rifle again on a silent day.