At the range where I work on the weekends, I had a fellow who had the same problem with his .300 Win Mag, you should sight in at 100 yards unless your range restricts you to 25. There is really no way to tell, seen guys get pretty good 3 or 5 shot groups in the X ring at 25 yards, only to be 3-4" high at 100 yards. You just have to shoot and see.