Duracoat doesn't require heating for curing. It comes in just about any color you could desire, and is supposed to work well. Personally, as I mentioned in another thread, I'd just pick up a can of Boesheild. It's a rust protectant that was originally developed by Boeing for aircraft parts, and I've found it to work really well. Just spray everything metal down and let it dry to a waxy coating. Cheaper than any finish and doesn't require the gun to be perfectly degreased and taken apart.