Don't forget about good old parkerizing too. I've got a couple of rifles that have been parked, and they stand up to the weather very well. One is a Remington 7400 that has all kinds of places for moisture to hide, and I hunted in a complete downpour for two days straight without any rust problems. I just wiped it down at night, after the hunt, took it apart for a thorough cleaning. No rust anywhere. Good testimony for Outers Sheath protectant if you ask me. Parkerizing still works for the military, and their rifles absorb more abuse than yours ever will. Parkerizing is usually cheaper than the other wonder-coats too. It cost me $85 to have my rifle done, with shipping included. If I had to pick a wonder finish, I'd go with cera-kote or something from Robar. I'd just leave the stainless bolt alone. Anything you coat it with will eventually get rubbed off by working the bolt, and look kind of nasty.