The S/S is made of different metals. S/S will rust.I have a friend who has a Ruger Security Six. It was his salt water boat gun. It was rusted and pitted some.I wouldn' t be alarmed over this. Take some 0000 steelwool or some Scotch Bright with some light oil and it will come right off. Go over it very lightly so you don' t change the guns original finish. As far as your misfire.I had the same thing happen last year with my Ruger M-77.I think what happened in my case the bolt wasn' t in the fully locked position.It' s possible it was bumped and I didn' t realize it until I went to fire.I ejected that round and chambered another. The next day I rechambered that misfired round and it fired instantly.If you would feel better take it to a competent Smith.My Ruger hasn' t missed a lick since that one and only misfire.I thought at first it was that round but it proved to be the rifle.
Ruger Redhawk