The few wild boar I have killed (175-290 lbs) were with a .270 Winchester with handloaded 130 grain Nosler Partition bullets at about 3,050 fps. All were one shot kills in the coastal plains, rolling hill country of Central California. This has been my pet mule deer load for more than 30 years. Actually, as it turns out, it's just about my pet everything load.
In one boar hunting camp at the end of the day, a bunch of guys were telling war stories about near death experiences with charging hogs. The guide was an experienced hunter and rancher who'd lived in this area his entire life. I asked him about these war stories and said how could I have made so many one shot kills with my pet mule deer load in a feeble .270 in light of all the near death experiences of these other guys? He just rolled his eyes and shrugged.
Later, when we were riding in his pick up alone, he admitted he'd had a few scary experiences while getting up close and finishing off wounded hogs with his .357 magnum pistol after they had been wounded by poor shooting clients. He said most of their stories were "bullsh*t. If you use proper loads in an adequate caliber, (i.e. .270 or bigger) and you can shoot, you'll be ok. He said the .243 is not enough gun for wild bore and he had had bad experiences with it. His personal rifle was a .270, but that he had seen great results with the .338 Win Mag and that he was impressed with the 8mm Mauser. The important thing was good shooting.
I agree a larger bore rifle would be more appropriate for the really big ones in thick cover. One of my boars was heart shot and he took off running for about 85 yards before dropping dead. I guess I was lucky he ran away from me instead of toward me. I might have been killed armed, as I was, with nothing more powerful than my feeble .270.
