I have a shooting shed that I shoot bench rest out of at up to 110 yards. In cold weather, anything below 50 degrees I heat the shed to around 75 degrees since I usually shoot for a couple of hours. This causes a mirage through my scope since the length of the barrel is inside the 75 degree heat and the air out side the window may be only 40 degrees or down to the 20's. The colder the weather the worse the mirage is. Anyone else have this problem and how to cure it.