I am fairly new to ELR (1000+ yards) for big game. I am now looking at getting a custom long range rifle built but wanted some feed back and ballistic information on what caliber would be the best. I really am hoping to understand what caliber and why. Last October I killed a big horn sheep at 1325 yards using a custom made rifle. Now I want to make one of my own but want to make sure I am making the best decision on the caliber I choose. Some have suggested the 338 lapua while some say you need a chariot to hunt with it. Others suggest the 6.5x284... While no data has been given to back up the suggestions I have received.. Thanks for all of the help!