Every caliber and make of cartriage has fail to kill an animal quick enough at some time and every bullet has fail at som point. We have to look beyond the sometimes and see what the real potential is. The 243 has kill a million deer without any problems is when paired with the correct ammo will kill any deer its pointed at. The shooter is what really matters and like was said before if you don't have any confidence in it you shouldn't use it till you work that confidence up. Bullet constructin and technology has come along way in the the past 20 years making questionable calibers suitable.