After helping with two science fair projects at different times involving coating bare pieces of metal with all manner of oils,greases, and waxes (including Ren. Wax) and then leaving them out in the rain and snow for a couple of weeks I tend to use WD40, petroleum jelly, and Break Free as my main rust protectors for my equipment. Bore Butter worked really well too if you are a black powder shooter and have some around. To the poster that said WD40 is just mineral oil I was wondering where you got that info? I have always heard WD40 was just a temporary coating too but it did better in the informal experiments we did out in the elements than the mineral oil and a lot of other things, at least for a couple of weeks.