The military and industry that need long term storage of guns or machinery that need protection from rust no longer slather on any greases.
That requires too much time to prepare for storage and way too much time to remove the coating.
An additional problem is, it's too easy to miss a hidden recess and find rust when it's unpacked.
Today, the best product is the vapor barrier system.
This is a chemical that produces fumes that surround the gun and eliminate any chance of rust, even in hidden areas.
Best, to put the item in use, all you have to do is open the bag, wipe out the bore, and possibly add a little fresh lubricant to key areas.
The best systems are what was known as Z-Corr now Bluguard, and Gun Wrap VCPI paper.
The Z-Corr/Bluguard system is a bag with the vapor barrier material inside. Just vacuum out the air and it's protected as the vapor drives out any residual air, and surrounds the metal.
Gun Wrap is sheets of treated paper with which the gun is wrapped, then stored in a special plastic bag.
Again, the vapor drives out air and surrounds the gun with the vapor.
Used properly these methods will protect a gun for from 10 to as much as 20 years.
If using the Gun Wrap, DON'T use ordinary plastic bags.
Standard plastic bags will pass moisture and allow air in and the vapor to leak out.
The special "Hard" plastic bags are made of a plastic similar to the plastic bags that electronics are shipped in and won't pass moisture or air.
BROWNELLS/BLUGUARD VCI VACUUM SEAL STORAGE BAGS | Brownells
Gun Wrap vapor paper.
BROWNELLS GUNWRAP™ PAPER | Brownells
Special "Hard" plastic bags:
BROWNELLS TRIPLE TOUGH™ PREMIUM STORAGE BAGS | Brownells