What was the damage to the lioness? Seems that had to be a lot of damage when it didn't exit and looks like that. So maybe not a bullet failure. I say that because I shot a mule deer at 150 yards with my .257 Weatherby. Bullet shattered the neck and was found in the left blackstrap a few inches behind the shoulder. It lost its pedals but l didn't see that as bullet failure.
It's the bullet on the left