I would never use a 243 or 7/30 to go after elk with. I would want something heavier. But, to each his or her own. The before mentioned rounds will work if placed properly as one can see, but I wouldn't risk it. I haven't taken an elk, but I haved killed a big Nilgai bull w/ a handgun and they are similar in size to elk. Nilgai do have a very tough hide, it is unbelievably thick. It's not quite like the gristle sheild on a boar though. It's more like heavy, thick skin than cartilage.