Depends on the SS you are talking about. 416 still contains plenty of carbon otherwise you couldn't machine the components economically. 17-4 stainless seems to hold up a lot better the rest will still rust if not taken care of it will just take a little longer. If I had a stainless rifle it would be teflon coated or plated with something if I were to hunt in Alaska or near the ocean. Better black powders being produced today and you'll have no problem with internal corrosion. Point is you have to be careful with both and wipe both down . I have had a stainless muzzleloader rust up rather nicely when hunting in wet..snowy conditions for more than a couple of days...I have also had stainless steel limb bolts on a Bow rust up during a hunt where it rained one day out of 7.