I killed a bull with a quartering away shot as it was traveling fairly swiftly through the woods. My 7mm bullet(7x57) made it from the last rib on the right side all the way to the heart. Killing the bull. The bullet had enough gas to get through the heart but not enough to do any damage to the front of the rib cage. I did not find it but it must have been in the chest some where. I have switched to a stouter constructed bullet in a .300 for my elk hunting and their should be two nice holes on any reasonable shot.
Smaller calibers will kill , but I would suggest people stick to the largest calibers they can shoot comfortably. Just out of respect for the game.
