Just get you one of these (you can find em for about $20-25 if you search, or fleBay) and blow it out every week or so while you're watch football (or whatever) at night and reload. All you lost is one charge of powder (and any moisture it collected) and you don't have to do a full cleaning (or wake up the neighborhood by discharging it by firing it) and you'll take away the concern that it's sitting there rusting while load.
(forgot to mention: [if you haven't seen one of these]
you can catch the pooted-out (technical term)
ball/bullet and patch in a box of rags/newspapers and can reuse)