I think that revolvers, given their nature, should be exempt from this. It'd also give them a bit more of a niche to occupy when compared with the rest of the semi-automatic handguns in the game.
By this logic, it might also make sense to have a similar situation with pump shotguns, even though those are several times more mechanically complex than a revolver is, and shells aren't typically as water-resistant as cartridges. Perhaps the break-action shotgun could be exempt.
Thoughts?