As winter is upon us...

[The War Wagon]

Question, is it ok to keep ammo in the basement, but in ammo cases?
If it gets kinda cold in my storage room, will it hurt or ruin the ammo??

CONSISTENT temperature, is the key.  Heating & cooling leads to condensation, and then corrosion.  And the primer will fail, before the case fails.

Keeping it in a metal ammo can helps.  A little desiccant pack, if you're really worried, helps too.