It would depend on the terrain..
I would think a .270 would be a lot up close, but for long shots it would be good.
If shots are shorter, I would think a 30-30 would suffice..
IMO..
But I will be interested in other peoples opinions..
If I may, I would like to redirect you to a site with some great information regarding boars. Not my site, but I like to use it for reference for friends or others who may be interested in hunting hogs...
Marlin 1895 lever action in 45/70 for distance. Thompson/Contender or Encore 30.30 medium range. 45 LC single action, or .44 s&w revolver for up close.
Some folks use a spear.
.22 LR back of the head will work also.