Hoppes 9 Lubricating Oil is a favorite of mine for locks an triggers an such, and for storage on a typical basis.
If I'm putting something away for the season it's LPS II.
You'll see and hear all kinds of "Hoodoo" and "Mojo" an olde secret ways an methods associated with Black Powder rifles.
The truth is, they get really dirty-really fast and because of that, they require attentive cleaning.
They need plenty of water(with a little soap) to rinse away the salts and hygroscopic fouling of the powder and caps. Then the metals need to be dryed well, then the bare clean metal needs to be protected from the environment,,(oil),, and a good oil that'll stick.