"100 degrees in the reloading room" Room may not be wet anymore but I bet the ole crack will be
Seriousley, my dad had the same problem his reloading room is huge and he had rusting problems so he bought one of those things that you spelled correctley

and a can to leave in his safe . but that didn't fix it completly . my dad installs epoxy sealents in concrete floors all across the country he sealed his concrete floor with some industrial stuff ( i don't remeber the name of it) and it fixed him right up . Does your loading room have a concrete floor? if so your probably getting moisture coming up through the concrete.
BigBick