ben,
your hunch is similar to mine.
that is that pigs are very susceptible to shock, and faster opening bullets are very effective on them.
that is not to say that any 22 centrefire is ideal for pigs, as the fighting pads on big ones are quite thick.
however well aimed shots will work.
velocity works well on pigs.
for some reason it is often taken for granted that pigs are always shot at close range hastily.
even in close country, often longer shots present.
if you are in country where a shotgun is igeal and will not limit shots, you are in pretty close country.
in there big mags are a hindrance because you only see a target fleetingly and fire few shots.
the old ruger 44 mag semiauto with a 4 shot mag was good here, and had the advantage over a shotgun of being good out to 100 yds, lighter, shorter, and less recoil.
before the 17 rem existed, I had a 17/222imp magnum.
it was only effective on pigs with a brain shot.
I suspect that the modern ballistic silvertip could be the same bullet as the nosler ballistic tip, but with a different colour tip.
they certainly started out that way.
totally unrelated to the old original tin coated silvertips of yore.
you might well fing that a std 55 gn soft point flat base sierra bullet would suit your 22/250 job very well.
also the 63 gn sierra soft point will be stable in a std twist 22/250. and handle game animals with a modicum of success.
bruce.