Wood % moisture and relative humidity are two differing things. As I recall, iron in open air stops rusting at relative humidity below 20%. I can't remember what average relative humidity will stabalize wood at 12% moisture, but am thinking it is above 50%. I think you can over dry wood and risk cracking it and unseating bedding. The biggest risk comes from rather sudden, big and prolonged changes in relative humidity. A gun used mostly in AZ, for example, might be stored at lower RH than one used mostly in FL.
