Speaking about ballistics...I was wondering how altitude plays in. I live at 118' ASL and sight in at home. I hunt near home at low altitude and often go to my deer camp which is nearer to 2000' ASL. I never detected any change from home to camp at zero for 100 yds. For the past 10 years I have hunted elk and muleys in Colorado at up to 11,500' ASL. I always sight in again in the valley at 7500' to make sure the gun didn't change due to the trip. I always tweak it so I am 2" high at 100 just to push my reasonable bullet drop out to 300 yds since I don't have a BDC reticle. I never had to shoot that far and to the best of my memory a 200yd shot at the muley in my member page was the longest. All my elk were less than 125 YDS. Just wondering how much our resident experts would say a 30-06 shooting factory ammo with a Barnes TSX 180 gr would vary according to altitude.