Yeah bore butter sucks! As one person put it, butter is for toast!
I really like birchwood casey Barricade or for heavier long term storage protection, RIG #2.
Just soak a patch after everything it dry, swab the bore, give it a few minutes to dry " both produce a protective film coating" mop up excess oil with one or 2 dry patches and its ready for storage.
Before i load up next time, i use one patch, spray it down with birchwood casey gun scrubber and swab the barricade or rig out. Dry patch, load and go have fun.