+1 on detached building - if you can. I'm fortunate in that I have a heated/cooled shop in the barn, (actually a 30x40 oversized garage) for my firearms hobby. I'm unfortunate in that I now have more ammunition than room in the shop. Been thinking about getting an old non-operative chest-type freezer for the unheated barn area to store ammunition in. Maybe I should be considering a small refrigerator for primers?