Hot damn, a chance to brag up my little inertia gun. My marsh blind is loving called "the mudhole" for good reason:
And the dog isn't the only thing dealing with its namesake:
That Benelli 20 is out there every open season morning without seeing much maintenance and is in no danger of losing its spot. Last time it was dunked, the dog flipped it out of the boat into slop so deep and thick that I found it with my knee. Unloaded it, swished it around in the cleaner surface water a bit, checked the barrel and went back to hunting. Though I did take the rare trouble to give it a good cleaning and drying out that evening.
But to what I gather your real question, gas gun reliability when wet: I see a lot of semis through my commercial blinds, and most gas guns are fine in heavy rain. With the 1187 being the only one I can recall rain boogering, and that was a case of unspent powder sticking and apparently acting like sand in the action, rather than a gas related issue. Haven't seen but a very few actually dunked, and don't recall any of those that were hinky afterwards, at least not in the short term.
If you think I'm wrong, you might be right.