Do your polishin first with graduatingly finer wet/dry sandpaper. Your finished product will depend on your sanding....use something strong to degrease the parts to be blued....after each coat of blueing, rinse in water, dry, then degrease if you touched any part with your bare hands, then blue again, do this repeatedly til you reach the desired effect. Oh I almost forgot....get the old blue and any rust off with the blue/rust remover! Take pictures, and post them....folks on here love to see that!:up:
I used a Birchwood Casey bluing kit that I had bought at Gander Mtn. to do my muzzleloader and it turned out great. It had everything that you need to blue a barrel along with the directions on how to do it. I would recommend getting one of these kits if you are going to re-blue a barrel.
I have a couple of old emails that I saved as text files. They have a lot of good information on how do it yourself. If you would like a copy of them I would be happy to share them. I ended up using black oxide instead of the blue, only because it was easier.
I'll put in a 2nd vote for the BC kit. I've gotten great results with it on a couple of old shotguns. I haven't finished them yet, but what I've done looks good. You might also check out the instructions for Brownell's cold blue kit at www.brownells.com. It's a lot more in-depth than what you get with the BC kit, and most of it applies. Good read.