This is how I look at this subject and this is just my personal opinion. First I don't believe in 1 type/style of bullet for all game. I match each and every game animal with a specific bullet/load/caliber. Bullet failure to me is when my bullet cannot get to and destroy the vitals of the game animal that I'm hunting. I think some of what we consider bullet failure are just poor initial bullet/gun choices....I don't think that a 400 gr solid from my 416 Barnes is a good choice for deer, and neither do I believe that a 125 gr BT from my 300 Whisper is supposed to reach the heart of a Hippo...it would be hard for me to blame the bullet if I made the above poor choices....just me.