RE: 30.06, .270 or 7mm
i have never hunted hogs so i can't base my opinion on that. but i would go with a " short action " caliber. something that you can find ammo almost anywhere and won't break your wallet.
308win, 7mm-08rem, 260rem,
the 308win is about 100FPS +/- under the 30-06sprg. just that not real good going over 180gr.s