Trev..........I have to disagree with you on this. A bullet can indeed fail and still terminate the animal in question, the failure witnessed in this case is cup/core separation. Regardless of the outcome to this specific animal, the bullet still failed to retain it's integrity. Given a different angle the bullet may not have been fatal to the animal, causing not only a bullet failure but a lost elk as well. This is exactly why I find it essential to recover my bullets when possible and evaluate their performance. I have yet to have a Nosler Part or Accubond fail to perform as advertised and use both with the utmost confidence.
As far as no perfect bullet...........well there is no such thing as a perfect ANYTHING, but I have to say that performance of the Partition and Accubonds come about as close to being totally predictable and thus perfect as this game gets. My discussion here is in reference to the big ungulates of NA and plains game of Africa and should not be carried over to big bears or other dangerous game.
I use these two because of my own successes with them and others with whom I have hunted while using these bullets. I have reservations with the homogenous copper bullets as I have witnessed total failure to expand in one case while using a TTSX with impact distance of between 50-75 mtrs. This deer was tracked down and harvested that day but the zero expansion was very evident with the TTSX hit. I have also heard stories from other very reliable sources of similar experiences, so you don't have to hit me over the head, I won't be using them again, in that cartridge.