Roskoe hit it right on the head- bluing is nothing more than a controled rusting- it doesnt work on stainless steel alloys. The products he mentioned are excellent, but you might also try gunkote or a similar products availible at Brownell's if you want to do it yourself. I did my 7mm that way and was pleased with the results. Just follow the directions to the letter, degrease the snot out of it and then degrease it again (wear gloves too), and keep your hands off of it until its cured at the proper temp. Good luck!