I had a blue marlin guide gun refinished in matt hardchrome after the first use in Alaska. It had a “ rust worm” or two starting after that one trip.
I used an outfit in Tampa, Fl. but I can’t remember the name.
I have no regrets doing it. Came out great looking and it’s a breeze to clean and not a spot of rust in over 20 years now.
So, in short, hard chroming works well for rust prevention.

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“Look life in its iron face”