I have killed hogs here in Texas with .223 Rem, .243 Win, .30-30 Win, .308 Win, 7mm Rem Mag, .270 Win, .30-06, and 12 gauge slugs.
I have killed the most with .223. I hit them and they go down. No, I am not William Tell with a rifle. Don't believe all of the board chatter. It doesn't have to be a perfect shot. An imperfect shot with a small caliber generally leads to a more perfect follow up with hogs unless you are talking about really large ones (i.e. > 200 lbs).
A 45-70 will take them down with extreme ease. Happy hunting! Post pics when you get back home.