Tools: various grits sandpaper, 220, 320 and 400 should suffice. Hard but flexible backer for the paper, something that'll conform to the radius of the parts so as not to impart a wavy surface. (Take extra care around sharp edges so as not to soften them.) 0000 steel wool, oil-free. Not hardware store wool as it has oil in it to inhibit rust while setting on the shelf. (I use Liberon brand wool.) Nitrile examination gloves- use after achieving 400x surface every time you touch the barrels. Acetone- to wash the barrels (and the fresh gloves every time you put them on)- I can't stress enough the need to totally de-grease everything once the polishing is done, and keep it oil-free from there on out.
Bluing solution: close your eyes and pick one of the couple that Brownell's sells. There's enough in one of those bottles to do a few guns, but that's the way it is. Follow directions on the bottle. Use the 0000 steel wool to card the rust between cycles.
A "sweat box" is handy to promote even rusting. You can build one in ten minutes out of scrap plywood. PM me for details.
A means of inducing boiling water or a hellacious amount of steam to the rusted parts. For barreled actions, and a couple sets of SxS shotgun barrels I did, a piece of PVC pipe big enough to hold them is all you need- put the barrels in there and fill up with boiling water and let sit for 10 minutes. Remove from tube, card the velvety black rust off with the wool. Repeat the rusting/boiling/carding cycle as often as needed until nice uniform blue-black finish is achieved- anywhere from four to six times is typical. Don't worry about the bores- the boiling hot steel will evaporate the water out of them right quickly. Push a dry patch through them if you feel it necessary.
After the last carding, hit it thoroughly with WD-40 (the only legitimate use for the stuff IMO) to drive any moisture out of hidden crevices. Wipe down and slather on gun oil of your choice. (Preferably all this is done while the steel is still hot/warm.) Do the WD-40 outside as you do not want stray molecules of the stuff contaminating your work area.) let sit overnight, wipe off, put the barrels on the gun and go out and shoot stuff with it.
That's it in a nut shell. Feel free to PM with questions/clarifications.
