How many right answers does he need? There's probably a minimum of 20 calibers he can use on elk. I've taken the majority of mine with a 30-30, and lately a muzzleloader.
Just get a 30-06, and go hunt. It's not that complicated.
Now we've moved onto hunting methods. Well, we were, but I don't want to argue about it. I tried to word my post so it wouldn't turn into a debate, but that's not possible.
I'm done.