I rust blued a 1911 i put together Interesting project, came out good but i didn't do the barrel. I think if i was doing a revolver i'd make some plugs out of wood dowels for the cylinder and the barrel during the boiling cycle. I also would recommend making a little "sweat box" for the rust cycle. A cardboard box with a light bulb(for heat) and a open pan of water inside the box to generate a little moisture would be a good thing.