I live at 1500 feet. We hunt at 11,000 feet. Higher altitude makes mine shoot high so I have to lower my scope 5 clicks (1.25 moa) when we head to the mountains. I shoot a Sako finnlight and use federal premium 300 win mags in 180 grain barnes TSX.
My heavy barrel Sendero which shoots hornady heavy mags (300 win mag also) seems to not have any deviation because of altitude changes.
I have no explanation, but the point is that you best confirm your zero when you first get there. Just find a safe spot and do it. We always show up at least two days early to zero and hike in.
