Well, this is interesting, seems to me that is the reason to check zero often on a hunt if you can. Jack O'Conner wrote of this. I live in CT, so I zero my rifle here in Summer its warm, when hunting season comes long its cooler, so I check to make sure My bullets go were I am looking. Fair enough, my land is just 300 feet about sea level. I go to Colorado to hunt elk, and I am now at the 9000 foot level and low temps, well its cheap insurance to shoot a few shots at a target to make sure my bullets are hitting were they need to go. We get all tied up in knots with 1/2 inch groups and loads and when the seasons change, the power is crap or what have you because our zero is off a bit and the group we just shot is well bigger than than 1/2 inch group we shot in shirt sleeves in July in pretty still air, never taking in consideration the clothes we are wearing while hunting, or the wind. It must be because of temperature Sensitivity or some thing else. Scopes have adjustments for windage and elevation, and they are not glued to one spot.
