there is a hollow point 150-151grn mold that is VERY popular over here....guy in Tokoroa casts them and sells on trademe.... Ive played with them quite a bit...MAJORITY of folks serious about subsonics use these if $$$$ are tight and the lehigh fracturing if $$$$ no issue.PERSONALLY I believe the 150hps are about as good of .308 cal subsonic projectile as you can get.....the ywill exit most animals..now granted a big pig over here is 200lb you lot have some very big fellas.... if I was using subs on pigs,I would want mag with potent supers on hand in case things got hairy in a hurry..better to apolagise for making noise than for ambulance turning up to rescue you after getting ripped by angry wounded boar.
the 151grn hp is same mold that throws 170 as aflat point...so probably talking same boolit as the others.
any pig under 100lb I wouldnt muck around and just shoulder shoot them. behind ear is ideal,but not going to be feasable once they are on the move.