I can vouch for the 30-30 as my boys routinely go to the woods sporting twin Marlin 336C's. They take a lot of hogs with the 30-30.
You don't need to be hundreds of yards away with hogs. Get close...and they don't take it well in the neck or head.
I had 250 rounds of 7.62x39 (someone gave me) that I gave away, because I don't have a rifle in or shoot that caliber. Interesting bullet and probably just fine as "hog medicine" too.
Shot placement is important, but not nearly so as the confidence of the shooter to place the shot where he wants it to go.