The first time Gregg shot one of my XP's, he set-up on the hood of my Tahoe with a bi-pod and a small field bag at just over 500 (closer to 550 yards I think).
His first shot was so close to the bull, and he made this comment, "That's not possible."
I said, "It is too, you just did it, now do it again."
And he proceeded to shoot even better.