I hunt hogs for meat, which means 120 lbs. or less. Any larger and the meat is pretty rank. I've killed all of mine with either .243 or .25-06 and good placement. I have seen them killed at that size with .22-250.
I'll tell you now that on one occasion I hit one with the .25-06 a little too far back and low from where I wanted. The shot rolled him but he got to his feet with no trouble and took off running with the rest of his buddies into mesquite-cholla-prickly pear scrub, leaving no blood trail. Hogs are surprisingly quick and I already had my gun off my shoulder (I learned something that day)- he didn't give me any time for a followup. Call me a slob or unethical but I did not follow him into that alone with no dogs and armed with a scoped long-barreled rifle. If I'd have had dogs, a short barreled shotgun with slugs or a heavy hunting handgun I might have tried it.
The largest hogs I have seen taken were between 250 and 300 lbs, one with a 7mm mag and the other with a .444 Marlin. They were taken with less than perfect shot placement, but still one shot kills.
If I were going after the larger ones and I didn't have a couple of 8mm Mausers around like I do I'd combine the advice of Gizmo99 and H&H,hunter. As a matter of fact, my next non-milsurp bolt gun will be either .308 or .30-06.