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Old July 9, 2013, 07:37 AM   #8
tobnpr
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Join Date: August 1, 2010
Location: Tampa Bay
Posts: 3,122
Quote:
If you shoot your stuff into no worse than 3/8 MOA through 1000 yards, then yes, worry about spin drift. Best wishes reading the wind past the first 100 yards and making exact corrections for it all the way to 1000 yards, too, as the wind drift for each yard of bullet travel's a lot more the closer the bullet gets to the target. You can only measure wind speed where you are at; good luck estimating crosswind speeds at various points downrange to the target. The wind speed's faster at the highest point in the bullets trajectory above the line of sight than at the muzzle and target; how much depends on the terrain. And a 1 mph crosswind moves .30-06/.308 bullets about 10 inches at 1000 yards.
Point is well taken. The effect is about the same as a 1 mph full-value crosswind- but, I think it's important to know it's there, and when combined with the Coriolis effect, drift is compounded.

For target shooters like myself, it's much less of a "big deal" because we have the luxury of walking-in our subsequent shots, automatically accounting for non-wind driven drift. But for a long-range hunter, that needs a first-round hit, seems that it's critical to understand and account for it.
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