No expert here, but I was shooting yesterday, off a bench with front and rear rests with a couple of my PCP air rifles, the BSA Scorpion carbine / .177 and the Air Arms S 410 ERB / .22 cal. There was a variable but reasonably strong cross wind blowing left to right while I was shooting. I estimate 5-10 knots with gusts of maybe 15-20 knots at times. It was breezy enough that I had to keep a tin of pellets on top of stack of target paper to keep them from blowing away. My best wind indicator down range was the paper targets flapping in the wind. When the wind picked up, I couldn't shoot at the target, which was on a clipboard, because it was constantly flapping in the wind. I had to tape the bottom edge to even shoot. Both rifles were zeroed at 30 yards, but in a more steady crosswind, the AA 410 with JSB 18.1 grain pellets was, as you would expect, much less affected by the winds. I was still holding about 1/2 inch groups at 30 yards. The BSA was shooting 8.75 grain Beeman FTS pellets and they were all over the place. As an exercise, I took a sighting target with 1-inch grids in the background and started trying to shoot at the intersections of the lines, 8 shots down the left hand edge of the target with no compensation. The pellets were drifting right anywhere from .5 in to just over 1.0 inch at 30 yards in that crosswind. I repeated the same series of shots coming down the right hand edge of the target, trying to guesstimate the windage compensation (I didn't reset the scope) and did a little better. One thing I did notice is that because of terrain (where the trees and shrubs are in my back yard) it seemed like the wind I was feeling at the bench was often very different from the apparent wind speed at the target. A gust that blew the targets around on my bench might not affect the paper target on the backstop down range, and vice versa.
