I would rather put a well placed 7.62 X 39 round into a hog than a .223. I would think that the heavier projectile with more frontal area would be more effective. But I have to admit that I've never taken any game with any of my 3 SKS rifles and have also never hog hunted. I'm just guessing here ... and others will certainly chime in with more experience than me.

Assuming a properly constructed bullet is used I'd go with the SKS. There are plenty of good factory hunting ammo for the 7.62 X 39. My 3 SKS rifles are plenty accurate enough for hog hunting at stalking ranges. You gonna be alone or will you have backup along?