The modern storage method used by the military and industry is the VCI Vapor barrier technology. This is more effective than any other method because the vapor completely surrounds the gun and doesn't require getting a lube or grease into every tiny area.
VCI is a material that forces out air and moisture and replaces it with a vapor barrier that prevents any rust.
You don't have to slather the gun with greases or Cosmoline, and all that's needed to put it back in service is to wipe out the bore and lubricate it.
There are special "hard" plastic bags made with the VCI material inside.
All you have to do is wipe finger prints off and seal the bag.
You're rust free for anything from 10 to 20 years.
A popular brand is Z-Rust. You can buy VCI treated bags on Amazon or direct from Z-Rust.........
https://www.zerustproducts.com/produ...st-protection/