I have done bluing before. We made our tanks, burners and stand. If I had a choice I would prblably moly or gunkoat a AK. If I was doing another custom mauser, I would blue. The true beuty of blue is in the apperance, not in the durability. There is nothing prettier than a high gloss super dark blue on a nice rifle. The system we used was
1. degrease and strip all parts of blue.
2. Boil in Brownells caustic cleaner (stuff is nasty) 15-20 minutes
3. cook in clean water tank, tank must not have any oil or gick in it. (15-20 minutes)
4. Hang in hot blue tank. This has to be done at a certain temperature so regulating that can be a chore. Gets to hot, you get these crazy red spots, too cold and the blue wont stick. Keep in mind this stuff is like battery acid on steroids! Get this stuff on your skin and say goodbye to that piece of skin. We use a wooden stirring stick and by the end of the day the stick was soft like a bannana.
5. After blue dip, drop it in blue kiddie pool of clean water and "card" off all the blue goo, scrub bore, find all the spots that look like crap and try agin....lol...
^. When we were all done, the rifles looked great, I did a SRM in 7x57 with a douglas blank and a rollover stock and a Martini in 45-70 (shilen blank). Mauser turned out great, Martini lookes good but still need someone that can work with wood.
We did 4 rifles and it took 7 hours.