I have only used the XPB in my 454 and only for deer. I recovered one bullet from a doe that I shot at 152 yds. Entrance was on the high shoulder and bullet was recovered on the opposite side at the base of the neck just under the skin. Expansion was about as perfect as you could get. However with seeing the amount of penetration and recovering the bullet I would be very hesitant to use that bullet for larger plains game. IMO