I strongly recommend against trying to hunt feral pigs with a .22 rimfire, whether or not it's the .22 Magnum. Just not enough gun for a clean kill.
Well, a super-shooter who never misses the eye. That ain't me.
If folks are serious, I'd suggest a 12-gauge with slugs. If that's not allowed, go fishing.
If he's big enough to bother with to eat, you're talking at least 30 or 40 on up to 60 pounds, depending on what you run across. Adults are going to run 150/200 or up. Sometimes, way up.
They spook easily and run--but if wounded, there can be a serious personality change, and YOU better be able to run!
Many javelina have been taken with .38 Specials and .357s. The eye is the best target on those tasty little critters. (They're near-sighted; call it "vision correction".
) Few pigalinas will dress out over around 30 pounds or so.
Art
Art