I have used an old Stevens 12 bore with LG Ball from the Indian Ordnance Factories on pigs and if you go close (not a problem in thick Indian forests) they are very effective. Cylinder and Improved Cylinder should be fine. I read somewhere a long time ago (I just can't recall where right now) that modern rifled shotgun slugs worked better in IC barrels than in plain Cylinder ones, but the experts may correct me if this is wrong. I am just repeating what I read somewhere...

In addition to Chapuis, Renato Gamba and some others in Europe offer rifle sighted slug shotguns but the old smoothbores work very well if you go close - less then 50 yards - and do your bit.

Good hunting!