Storing inside a case is a crappy situation. Any moisture stuck between the foam and rifle will increase the chance of rust building up.
Without a safe, I store mine loose in the closet. It keeps air circulating, and easier to check once a week to make sure everythig is good to go. I wipe everything down with a rag with CLP on it, then a dry rag, and run a lightly oiled patch through the barrel (a drop or two, don't want it to be runny). Any dust or pet hair gets brushed off with a paint brush.
I've done this for 20 years on my (blued) .22 and never had a problem. Also do it with my Garand and SOCOM for over a year now. Parkerized weapons you shouldn't have to re do except every few years. Blued need to be rewiped every few months.
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If you HAVE to keep them stored in the case, and it's for long periods of time, you can vacuum seal them with a coat of oil on them. Kind of like the military stores them packed in cosmoline.
In any case, the trick is to put a very light coat of oil on them.