Newby question. My dad and I are just getting into long range shooting. My dad had his rifle sighted in at 100 yards. They sighted it in 3 inches high. He is shooting a 300 RUM with 180 SST's at 3485 fps. I wanted to find out what his zero would be because we are going shooting in the morning and I want to play with it a bit. I looked on the Hornady site and according to their calculator this round would drop 2.8 inches at 225 yards if it were sighted in for a 100. So at 3 inches would the zero be 225?