I just finished browning mine. This was my first time, but this is what I learned.... Strip down the gun,You will first need to remove the blue from all parts that you want brown. (I did this with the liquid blue remove stuff). Make sure you get it all, then use a cleaner/degreaser to get it really clean. (then don't touch it with bare hands, use cotton gloves!)
I purchased birchwood casy's Plum Brown. I used two vises to support the barrel, using a brass punch inserted in the muzzle and a pipe fitting to slip the breech plug into on the other end. Using a torch, heat small sections(about 6" and about 2 flats) at a time. Drop a little water on the heated section, if the water sizzles it is the right temp to apply your brown. (275 degrees is the temp your after). When you have gone through the whole barrel, rinse it off real good. I had to repeat the process several times to get the dark brown that I wanted. Next time I do one, I will clean and degrease between each coat and wear cotton gloves. (I wound up with some finger prints on mine using latex gloves).
I have heard that there are a lot of way to brown, but that is the way I tried and it came out pretty nice......Terry