I am going to organize a trip to hunt some hogs.

What is the best gun to do it with? I have a .22 semi-auto, a 12g mossberg pump and a 7.62 Reminton 700.

The contry we will be huntin in is pretty thick so I want to kill them quik.

I would take both your .308 & your shot gun with some sg's you could maybe sling your rifle and have your shot gun in your hands.

of those choices, I would go with the shotgun, loaded with slugs, magnums if you can. Exactly what calber is the 700? 7.62X ?...

My mates 15 year old son uses a Rossi coach gun to good effect in the swamps around home. Alas we are restricted to double barrels in Australia, your pump should be just the ticket. Stay away from the .22, you'll only piss the pig off
I use a 6.5x55 with a 3-9x scope (set on 3 in the thick stuff) and an open sight 8x57 mauser, for all my pig shooting.

Bakes

I dunno where you are from or what type of hunting you will be doing or the terrain, but in general, I would take the 7.62 98% of the time over the shotgun, and the .22 is out of the question. If you're using dogs, the shotgun unless loaded with slugs is out and if you are not using dogs, the possibility of having a longer initial or a follow up shot at wounded hogs certainly would sway me toward the 7.62.

I've got quite a few hogs on my ranch and, while I've killed them with buckshot, I use a rifle or a pistol 100% of the time now.

Crawling through cane brakes along a river might require a re-think though, but mostly go with the rifle.

Remember, hogs die easily if hit in the forward third, basically from the front leg line up to the head, but hit them just a little too far back and recovery will be unlikely.