This is a hard question to answer because mirage is a variable. In general, mirage effect is like what happens when you stick a cleaning pole into a pool. As soon as the pole enters the water, it appears that the angle of entry changes (or the pole bends). If you have your rifle on a solid rest, and you look through the scope, mirage will make it appear that the crosshairs are dancing around on the target. Reading mirage is an art form that you are always learning.