Have killed a few pigs here and there in the past 30+ years, mostly feral pigs in at least three states of the U.S.A., plus central Europe and warthogs in Africa (where in some places they're considered as much of a pest as our feral pigs). Have done so with over a dozen cartridges from the .223 Remington on up, and more than one load in some of those rounds.
This one was taken in Texas with a head-shot from one of Bill Wilson's excellent AR-15's in 6.8 SPC around a decade ago, and half an hour later took a coyote at around 200 yards. Bill is a pig-hunting fool, and in fact bought this Texas ranch primarily for pig hunting, though it also has some fine whitetails. Dunno how many pigs he (and his guests) kill each year, but it's quite a few, and at the time he thought the 6.8 with various Barnes TSXs was tops. More recently he developed the .300 HAM'R, which basically duplicates .30-30 ballistics in an AR-15, and feels it's a little better on big boars. Have shot one of his .300 HAM'Rs some, but not on pigs. (One thing I learned from Bill during our hunt was that while head-shots work great on pigs, shooting them in the middle of the neck just in front of the shoulders is equally effective, but allows considerably more room for a little aiming area.)
Have shot pigs from up close running to pretty long range, especially in coastal Texas where the sand-dune country can be very wide-open. That was with a 7mm SAUM, which crumpled them well. Also have killed them with traditional European boar cartridges (especially 9.3s) and in Africa with the .375 H&H, because was hunting other stuff considerably larger. It's all great, and so far haven't found a round that doesn't work well with the right bullet, shooter and conditions.
