Re: Wind Advice - can you help?
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I use a wind meter and charts to help me adjust for normal wind conditions but yesterday I was faced with a situation that I was unsure of how to deal with. I was preparing for a 400 yard shot with a 10 mph wind from 9.00 o'clock (full value) but after 200 yards a large wood acted as a screen and judging by the leaves and grass there was no wind for the remaining distance to the target.
Should I have calculated the wind for only the first 200 yards or is there a formula for this type of situation? Any advice would be greatly appreciated.
My setup is a 26" heavy barrel Steyr .308 155g Amax which would have given 12.6" of drift under normal conditions.
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IMHO, I would hold/dial for a half-value wind, i.e.: use data for a 5 mph 9 o'clock breeze.
I say this because the wind only seems to have effect over one half the course.
There is a lot of controversy about which part of the wind is most important, whether the greater angular dispersion at the muzzle will affect bullet flight more than wind at the target, which is now working on a slower moving bullet. . . no one of authority can seem to agree. In either case, you will only see the effect of half of the wind influence and a half value wind would get you 6.3" hold-off. Even accounting for a very minor difference in wind effect over "which half of the course?", you'll still end up with an extremely close first round impact.
The beatings will continue until morale improves.