Since you are doing a percussion revolver an easy and durable finish can be obtained with rust bluing and is the way many of the originals were finished.
Order some Art's Belgian blue from Midway. All you will need then is some distilled water and a pan large enough to hold the cylinder and barrel. Polish no finer than 320 grit and have some OOOO degreased steel wool. You can do it on the stove top as all you are doing is boiling water. With just a little care you can end up with a great blue job every bit as durable if not more so that hot caustic blue. Midway has a you tube video on this. Check it out.