Questions about safe long term storage of our guns come up fairly often. In the current issue of SAR, there is an article in the new products column that might be of some help. The Marine Corps originally asked for the product to be developed and is now using it for M16 storage after extensive testing.
Her's the link http://www.zcorrproducts.com/

I have used VCI vapor emitters in my gun safe and tool cabinets for over 20 yrs and have never had the slightest problem with corrosion. I store my guns merely wiped down with a silicone treated cloth. I have no doubts about the basic technology; it works.

OB