I watched them harvest full grown buffalo on the Triple U ranch in South Dakota using a 233 with FMJ bullets. They drive up to within 30 feet of the herd in a pick-up, roll down the window, pick a buffalo and bang-flop....... right behind the ear. Would I hunt buffalo with a 223 with FMJ........................NO. Give me a Buffalo cartridge like the 45-70 loaded with 500 gr. bullets.
The question isn't whether or not a particular bullet will kill a certain game animal or not it's what ought you employ in a certain situation. Range, fur or meat damage, danger from wounded animal, ability to place the shot(skill), experience, wind................ on and on, they all play a part to a greater or lesser extent. That's the challenge of hunting.
Oh ya, i forgot....... common sense.
JMO
Mc