Another thing is, your gun should be prepared to get wet. What I mean is, on many guns, there are springs and things in the trigger assembly that would be ok to coat with a thin layer of grease. I am willing to bet that 75-90% of the internals of a gun could be coated with a thin layer of grease, run great that way, get completely submerged in water, and still run great afterwards. To me, it is smart have a lubricant inside your gun that can resist being washed away due to water submersion.
Funny, I always disassemble and then hose a water wet firearm down with WD-40 which for some reason is a Water Dispersant which is what you want to do when you get a firearm wet, disperse the water from the weapon. I then wipe it down and use Breakfree CLP for final rust protection.
In over 35 years of firearm ownership and usage I have never had a rust issue.