Glocks have been the most resistant and forgiving. Hard chrome has also worked well, but I have had some fine rust even with it, and again, mostly at or under the grips. Ive had great results with Eezox on things that rust, and its what I use on my wipe down rags. Ive been using it on a couple of guns, my reloading equipment, and a bunch of tools in a damp basement for a number of years now, and not a spot of rust on anything Ive treated with it. Works well on carry guns too, but, like anything else, you do need to constantly keep up with it and wipe things down on a daily basis, especially in warmer weather.