ViolentPanda
Hardly getting over it.
if you are storing near three mil of weaponry in a fucking salt mine then surely a good chunk of it will be inoperable without the aid of a gunsmith and his toolshop. Salt is corrosive. Badly so. I'm not even on about how dated the gear would be, a webley is old but if a bullet comes out of the end of it, at speed, it works. But a salt mine? surely the vast majority of that equipment is going to be beyond fucked, scrap value fucked.
Most stored weaponry isn't kept in racks as in an armoury, it's crated and the individual weapons are coated with a greasy wax-type substance (naptha is quite good for removing it, but mind your fag!), so corrosion isn't usually an issue, and as the weapon isn't exposed to any mechanical strain in storage, there's not much chance of metal fatigue either. Firearms should be as solid and useful as the day they got their proof marks.
What's more likely to suffer from storage (even relatively short storage) is modern ammo, as modern smokeless powders are ever-so-slightly hygroscopic, which is why some of your American gun spods store their ammo in "environmentally-controlled" conditions.