Looks like Mythbusters are going to do another gun related myth of how deep underwater you have to go to be safe from gunfire. I think I saw a 12 gauge mossy shotgun and a 50bmg (again I think) in the commercial where Jamie appears to shoot at Adam in the bottom of a pool with the black shotgun.
http://dsc.discovery.com/schedule/episode.jsp?episode=34&cpi=24704&gid=11489&channel=DSC
http://dsc.discovery.com/schedule/episode.jsp?episode=34&cpi=24704&gid=11489&channel=DSC