http://www.youtube.com/watch?v=oKbWcPdTRBI I found this video it shows all the disassembly and reassembly you'll need for cleaning and lubricating your Mossberg 500. if you can't get the barrel clean you could actually remove it and soak it in hoppes. i don't think it would have any negative effect. On my guns, i always over-lubricate all moving parts and touching surfaces. then i put the gun back together and work the action a little bit. then i'll wipe off any excess lubricant. (might have to take the gun backapart to do that)


for your winchester, i'd take it to a gunsmith just to be sure i don't break anything.