The last few times I have shot in heavy mirage,I noticed I end up about 2moa low at around 900-1000yds.,Is this normal.Is there anyway to predict what the effects of mirage will do at certain distances?I am assuming the mirage is just making the target appear in a different spot than where it actually is.I find mirage to be the trickiest condition to shoot in.Are the effects of mirage alway's the same?