I guess it all depends on how long the storage period will be... but generally I use Inhibitor V80 oil or just good old
REM Oil. Both do a good job of preventing rust and displacing moisture, not floating on top of it or covering it. However both require a thorough gun cleaning before the next use, especially the inside of the barrel.
I've used V80 on my fishing reels foryears and none of them have any corrosion onthem at alleven with
lots of salt water use.... but it's really bad for dieseling if you forget to clean it out of the barrel first.
Believe me though, you'll only forget once