I live in central Florida out in the swamps and caretake about 2500 acres and hunt numerous other properties. We hunt hogs both still hunting and with catch dogs as well as trapping them. I have killed them using a knife, shotgun, bow, rifle, pistol, muzzleloader (I once beat one to death with a knotted chain after he had been hit by a car) and found that a hog CAN be killed with most anything. Shot placement is everything.
Any .30 caliber in the .308, 06, 30-30, 7.62x54R class is a excellent hog stopper and allows room for a slight error in shot placement but not much.
I regularly use a 6.5 Swede but am very careful about shot placement. My buddy uses a .270 and he hasn't lost one yet. A behind the shoulder shot is not the best place to shoot a hog. Their heart and lungs are further forward and lower than on a deer. I try for the base of the neck about 1/3 of the way up or a quartering away shot behind the last ribs up into the chest cavity. Put a heavy, premium bullet in the boiler room, and he is going down. By the way, I do not recommend buckshot on a hog beyond 20yds or so in spite of the fact that my wife shot one with a 20 gauge recently with #3 buck at 30 yds. I had to finish it with my handgun.
