This is good stuff:
http://www.brownells.com/.aspx/pid=1...UST_PREVENTION
I use it after refinishing a gun, but it also works great after a complete disassembly and cleaning. You just dip or brush the parts, shake off the excess, let it dry for a day or so and it will leave a very thin, waxy film that's more than adequate for a properly stored gun. The viscosity and penetration reminds me of crude oil: It's very thin and runny and penetrates everything (including your work bench, clothes and whatever it comes in contact with) so it can be a bit messy to work with, but it's very easy to get a good coverage and it's not as greasy as oil once it's dry. It also seems to "deepen" the finish a bit, especially on rust blued guns. It's not a lubricant though, so you will have to lube with something else wherever it's needed.