I have a problem where I live its only 900 to 1000 FT above sea level. I will be hunting in Wyoming for Cow Elk and where we will be hunting will be 7000 to 10,000 FT above sea level. So my question is how are my loads going to be at Higher elevation? Do I just trust the ballistic Calc? The farthest I will be shooting is 700 Yards. What do you guys suggest?