As far as the "WET GUN" question goes, I will agree with the before poster, You need to Clean out all the Water, Salt or Fresh and scrub all the internals with a soft brush, I like a Tooth Brush, but many others will do! Use a Good Gun Cleaner or Cleaning solvent and once all Looks clean and spanky, apply a few drops of oil to all the action area's and parts! That will leave it with a light coat of oil, if your gonna be in Desert Conditions or any grit filled envoronment, skip the Oil except for right on Parts and spnings and go real lite on that!
Guns Like the Rem 870 Shotgun, the MP-5 and the M-9 Pistol have gone with me on raids and got completly sumerged, they worked fine after and It pays to clean your gear before you relax after the action! Nothing weapons from the 1903 to the Garand and others have not seen and experienced, all ya gotta do is care for them after!