The basic question is how much does air pressure matter for wind drift, and why? I was just re-reading the thread about the 3871 yd sniper kill and thinking about the wind. Since air density has such an important effect on drag, it seems like a 10 mph crosswind at a lower air pressure such as 20 in Hg should have much less effect on a bullet at a given target range than a 10 mph crosswind at 30 in Hg. I ran a 1000 yd case for my favorite factory .260 Load on a popular ballistics solver with a 10 mph wind from 3 o’clock (full value right to left). The solver is giving my aiming solution as Up 31.2 MOA and left 19.7 MOA at standard atmosphere 59F and 29.92 in Hg. When I change the pressure to 20 in Hg (absolute) and 59 F, the solution is Up 25.5 and left 19.5, almost no change in windage. The elevation solution seems reasonable. If correct, is the low difference in wind drift because the relative velocity is > 2000 ft/s for the forward motion, but the wind speed is only around 15 ft/sec and drag is nonlinear with velocity? Still the calculated difference in wind drift seems very low for such a big change in air pressure.