I would suggest placing a rubber mat or something similar on the floor of your safe just to have something non absorbent where the muzzles are resting. But if your humidity level in the safe is kept below 40% you shouldn't have any problems with rust. Just keep checking them. You might want to run an oily patch down the bores also. I have been brushing a light coat of Breakfree Collector on all my safe queens and haven't seen any corrosion after several years. Storing long guns muzzle down is a good practice, it keeps the oil on the metal parts from seeping into the wood.