One thing I don't see mentioned on this board is the effect of mirage on shots exceeding 500 yards. When I did a lot of competitive high power shooting while I was in the Army, we stressed the effect that heavy mirage has on point of impact. Specifically, you aim at what you THINK is the proper target, but the mirage displaces that target. In addition, mirage is an excellent indicator of both the intensity and direction of the wind. Any thoughts?