I would definitly go for the Fully automatic shotgun, yes, the fabled AA-12. Submerge this beast for 10 minutes in water, and straight off you can firing this gun without any problems. Drum mag, great.
my favorite pistol=Python my favorite assault rifle=AK-47 tied with AUG my favorite sub machine gun=AK74U my favorite sniper=L96A1 my favorite rocket launcher= M72 LAW my favorite special= Ballistic Knife -from Black Ops