I live in Oklahoma at about 500 ft. elevation. I have a factory 7mm Mag Remington Sendero that I have had for two years. I recently did a mule deer hunt in Wyoming at 8,000 ft. elevation. I double checked my 200 yard zero in OK before I left and put it in the pelican case. To my surprise, when I got to Wyoming I shot several times at range and it was grouping 4 inches low at 200 yards. Does anyone know why the gun would shoot 4 inches lower in Wyoming than Oklahoma? I did not bump nightforce scope and shooting same batch of handloads. I shoot IMR 4350 which is not an "extreme" powder but I wouldn't expect different results and if any I would think it would shoot higher in Wyoming due to higher altitude. My MOA data out to longer ranges also proved to be significantly different as well. Any thoughts on what would be going on?