I am trying to train up for a competition. The competition suppose to be shoots no longer than 800 yards. I am shooting sub MOA at 100 yards right now. But I have never shoot over 400 yards before. I have a range finder on the way to help with accurate ranging. I am also using JBM calculator. I am running a 308 SPS tactical with a USO 3x17, a flat base, and a Harris bipod. Any other suggestions beside shooting and correcting the JBM calculations?