YES. Ever notice how everyone brags about "huge entry holes" with the Rage, but no one talks about the exit holes, for the simple reason that the rage does leave a big entry hole but lacks the penetration, and that's on whitetails. Now you're talking about an animal that weighs a good 4 times more with a much heavier and larger bone structure along with the fact that the average shot distance is longer, when compared to whitetails, and you're going to wish for as much penetration as you can get.
Go with fixed and simply errase any worrys about lack of penetration when the big shot on a 6x6 bull at 45 yards looks you in the eye.