Long term storage? I shove'em in the freezer they last for years, no need to oil either. Make sure to wrap them in Duct tape though, keeps the freezer burn at bay..........
I would suggest whenever storing long arms for long or short periods is to store them muzzle down.
Keeps the oil from soaking into and softening and staining the butt/tang area.
Thanks WarPig, looks like I will be shopping for a large freezer this weekend