Rust Blue is the way to go! At this point in my life I have probably rust blued about a dozen guns. Rust bluing is superior to hot bluing for a number of reasons.
Rust bluing requires not heating above 212 degrees and it also doesn't change the internal dimensions of the barrel. It is a slow process of applying a hyper thin layer of acid to the thouroughly cleaned surface of the metal which allows the metal to oxidize very quickly. It is then boiled or (in my case) steamed for anywhere from 10-30 minutes. The heat combined with the water turns the red rust that has formed into black magnetite. Magnetite is tougher than the steel beneath it. This entire process is repeated anywhere from 10-20 times depending on the level of coloring desired. Because it is slowly applied and lots of time is involved, a rust blue has more time to penetrate the surface of the metal and produces a beautiful matte luster on the barrel that can't be duplicated!
Hot or "caustic" bluing is done by immersion in a tank of boiling sodium hydroxide (used to increase the temperature) and a combination of nitrate salts. It will blue a rifle in a comparatively short time but the bluing, while in some cases more even and sometimes darker, is not as deep into the steel and therefore, theoretically, not as durable. Hot bluing was developed and used for mass production, not because it is better, but because it was faster and less time=less money. Winchester used to use vast steam rooms to rust blue until the early 1900's when hot bluing was introduced. They could now produce twice as many guns, without all the need for space and steam generation.
A rust bluing job isn't cheap, but it is worth it! As an aside, if your gunsmith can do it, Nitre Bluing all the screws sets off a rust bluing job beautifully. Somewhere on here I have several pictures of rust blued guns I have done. Check them out if you get a chance.