I've said this many times in many places but maybe some haven't heard it or perhaps don't believe it. I learned my lesson in 1976-77 in Handgun Silhouette, you just can't shoot hard cast at hard objects, especially at high velocity or you are doomed to fail. A premium bullet will not do that but cast bullets can break your heart if you break the rules.
The rules are, hard cast at high velocity on heavy bone is a no no, same way on steel we found out after much experimenting. Once we slowed down & softened our alloy we started to have success.
We referred to it as "dwell time" A cast bullet will do fine on a lot of bone but not a lot of heavy bone, especially if it's going fast & is an high antimony alloy bullet.
Big, heavy cast bullets are wonderful, I've used them all my life but I've never tried to drive them top level, you don't need to. The faster you drive them the faster they will fail on heavy bone. Also a nose profile that is too wide will work against you, you have to compromise a little.
I doubt I'll ever kill anything bigger than the elk, moose, bears & plains game I've already killed so I'll never shoot anything but cast. I do have a local guy who said I can shoot some slaughter steers for him in a few weeks, I'll use 3 different calibers. I've done this twice before but it's been a while, looking forward to it.

Dick