Gravity, drag and wind are the three major forces acting upon your projectile during flight. Wind drift is the one which causes most shooters to miss their target at longer ranges. The effect that wind will have on the projectile is dependant on so many factors, such as the range, strength of the wind, and the direction that the wind is blowing, along with the projectiles characteristics. At 360 meters, a typical AK round can drift as much as 73cm from its target in a 10mph crossind. This is nearly two target widths, and shows you why the AK round becomes ineffective at longer ranges. In certain situations you can find three or four different wind speeds and directions along your bullets flight path. Things can become very tricky if the shooter doesn't know how to account for wind correctly.
Understanding wind and how to account for it is a big deal. Our Sniper Marksmanship Manual comprehensively covers skills & techniques on judging wind speeds and overcoming the effects caused by wind, aiding you in correcting your bullets flight path and allowing you to start shooting at further distances. This will result in drastic improvements when you go back to shooting at close range.