Windage question.

[Josh11]

I dont know if many of you use the shooter ready program on the old 6br website, but Ive really been thinking of getting it. I am able to find the range hit the target but I can not get the windage down. My question is how do I find the exact windage.

For example: I have a 5 mph cross wind from left to right and at 700 yards with a mv of 2635 fps. At 700 yards the drift is 3.9 inch for 1 mph. After I hit the target it gives what the drift was it ended up being 13.6.
What formula do I use to get the exact windage?

Any help would be great.

 

[expiper]

HI Josh....the formuli for much of our ballistic computations are "just that"...they get u close...and by the time you do the math the wind has changed...!!....practice/practice....shooting is a very educational game...we study mechanical desighn....chemical compounds,,,,mad science..ballistic theory.....and we are still at the mercy of the wind....Roger

 

[Josh11]

But say if its a steady wind. On the shooter ready program, the wind stays the same.

 

[fdshuster]

josh: When you get it figured out, let me know. I've seldom, if ever seen a steady wind, and how do you know what it's doing between you and the target, especially at those longer distances? To me, it's all a crap shoot at best.

 

[memilanuk]

Could be a variety of things... difference in which BC was used to calculate the values, whether the MV is measured @ the muzzle or 15' down range, true moa clicks vs. IPHY clicks, accuracy/consistency of the rifle and the shooter's hold, etc. Lots of things that could 'stack' and are hard to nail down exactly.

Like the old saying... improvise, adapt, overcome

 

[Cheechako]

Josh

How do you know the wind was 5mph???? If the deflection at 700 yards was 13.6" and your formula says 3.9" per 1mph, that calculates to a wind of 3.5mph. Can you tell the difference between a 5mph and a 3.5mph wind?? I sure can't.

That's just one example of what could have you confused when you look at the target. It's a lot more complicated than that. Listen to what Mr Milanuk, fd and the piper said.

Most important of all, believe what the bullet holes in the paper are telling you. Ballistic charts are only approximations, at best.

Ray

 

[memilanuk]

How do you know the wind was 5mph????

Probably because the screen said so

Seriously, though... I think he's using Shooter Ready to practice... its been a while since I played with the site, but it used to have a pretty good rep for being a reasonably accurate simulation. I don't know if they throw all the little monkey wrenches I mentioned into the mix or not, though.

 

[Josh11]

Yep, shooter ready is a good tool to use, but I cant get to calculate for the wind. They give me all the variables I need to hit the target. Now putting the variables to use for the wind is a different story. I can guess on the wind and be fairly accurate but I want to be able to dial in for a one shot hit. Since the wind doesnt change.

 

[BoydAllen]

"since the wind doesn't change" ....what planet? Have you ever been to a short range benchrest match, and watched a whole field of flags? Wind is much more complex than you evidently think it is.

 

[memilanuk]

Hello Boyd,

The scope of the question is a bit different on this one. if you actually read the posts, he's working with a training simulator program. In the particular scenario, the wind is a constant 5mph. No, the real world isn't that simple. But in this particular case, what he said was accurate.

Monte

 

[BoydAllen]

Ahha! I get so used to seeing actual shooting questions, my skimming let me down. Thanks for being so diplomatic about pointing my error out to me. At least you said that I didn't read, rather than can't Looking back, I see what you mean. It would seem that the only way that I can properly understand the question is to find the program and give it a try.

 

[BoydAllen]

I tried it, and for the situation that you described, the range table showed a wind correction of .1 mil per mph., which would give a turret correction or hold off of .5 mil. When I held into the wind by that amount, and up by the appropriate number of mils (by dragging the sight picture) the plate went down. The mil corrections are angular, and because of this there at target value increases in proportion to the yardage. A mil is 3.6 times 7 inches at 700 yards which works out to 25.2 inches. The range table give wind hold off to a tenth of a mil. so there will be some discrepancy between the correction and the actual drift. Using .1 mil per mph times 5 gives a correction of of .5 mil which is equivalent to 12.6 inches at 700 yards. Close enough to actual drift for knocking down plates. Added later: When I got to higher cross wind I ended up having to give the indicated an indicated quartering less than full value to stay on the plate. I did a gesstimation at half value and stayed on the plate, at 700 meters for this I used the windage knob. After that I went back and tried half value on a slower quartering wind, and hit the plate. I found that the direction shown by the labeling in the box that indicated amount of windage correction that was being dialed in moved the bullet in the opposite of the expected direction. for a left to right quartering wind, I had to input .7 mil into "bullet impact right".

I did a little more research, and a quartering wind was said to be worth .7 of a full crosswind, so a 10 mph quartering would give the same drift as a 7 mph crosswind. Looking at the computed drift, it looks to be a close approximation. Finally you have your answer.

Monte,
Check my answer and see if it is a little better than the first time. If you find errors, let us know.
Boyd

 

[queen_stick]

Boyd, thanks for posting that. That cleared some questions I had as well.

Walt