Certain types of stainless has more carbon in it.
Beeswax and Lanolin in my leather boot wax.....any good to coat rifle?I think people mistake 'stain-less' with 'stain-free.' All stainless steel will rust, given enough time and exposure, but stainless is more rust-resistant than chrome moly. Anyone who has a knife made from, say, 5160, will see the blade stain/darken over time... often within 20 to 30 minutes of use! Stainless won't do this, but depending on the type of stainless steel used, it may be more or less susceptible to rust. I have a can of silicone spray and use that along with a silicone cloth to wipe off all of my stainless rifles and haven't had a problem. If I were going to a constantly rainy area to hunt, I'd break out the paste wax, pull the action and bottom metal from the stock, and give everything a good polished wax job. Having grown up in the Gulf South surrounded by swamp and marsh, I also use RIG grease on all of my blued firearms.