I assume you are talking about wiping down a rifle that has not been used.
Generally, I will only swab the barrel if the gun has been fired. When I clean a dirty gun, the barrel gets lubed.(I won't put a dirty gun in my safe.)
I like to keep the Rem Oil Wipes in the little packet handy in the safe.
If I pull a gun out to fondle it, or I feel like it's been sitting long enough to need a good wipe down, I'll just whip out a packet and do it. They are like Baby Wipes, and have a very thin lube that dries to a nice oily film. Great stuff for getting those finger prints off before sticking the rifle back in the safe.
It's quick, cheap, easy, and it seems to be working.
If I go so far as to pull out my cleaning supplies, I have an assortment of stuff I use depending on what I feel the requirements are.
Break Free CLP in the squeeze bottle is what I usually use to prevent rust.