Have you considered a good 12 gauge shotgun with slugs for the shorter distances? You could pick up a police shotgun at a reasonable price or maybe invest in a shotgun with different barrels so you could use it for turkeys, ducks, etc. A shotgun is fairly economical to shoot, can be easily reloaded for and is extremely versatile. You may even already have a shotgun ideal for this purpose.

I've shot 2 hogs with a 270 and both times needed more than 1 shot with good shot placement. I've seen hogs shot with 30-30's that went right down and one hog shot with a 450 Marlin that ran for about 100 yards. Larger hogs (200+ lbs) can be hard to put down.