I don't think you will go wrong with either style of bullet considering it is heavy enough. If you hit this big bull solidly he will be dead on his hooves. A 500gr. XTP is not a HP it is a FP, it will mushroom, but not like a HP. If you drive this bullet with enough horsepower you want have to worry about penetration, at 500gr. it's going to leave a Hell of a blood trail, if it doesn't die within a few steps of where it's standing. Considering a 385gr. BCHP (bonded core hollow point) gave complete penetraion out of a Competitor 50 AE on the Yak bull I killed. I have used Hardcast bullets to kill a Water Buffalo and a Nilgai. They did fine, but a bullet that mushrooms and still gives complete penetration will leave a Bigger exit wound. Everyone has an opinion and they both have good points. If you shoot good, it want matter what style you hit him with if the bullet is heavy enough to penetrate. No doubt a Hardcast will out penetrate a soft point, but a Punch Bullet will out penetrate a hardcast bullet.