From time to time I have to overhaul some of my unit's Bess muskets, and some are India origin and others are Miroku or Pedersoli.
So I use a PVC pipe, and a glued cap as some have suggested. I removed the barrel, clean it, and then submerge it in Evaporust. I usually put the ramrod in there too. It works for me, and there are other products out there too. I do the same for the lock, after disassembly. Then I put the used Evaporust into a use translucent water jug..., and let the crud settle, which lets me use the cleared portion again.
In fact I purposely will surface rust the steel on an India musket, then Evaporust it, to knock off the mirror like polish. You get a proper light gray when done.
After rust removal, I rinse and dry the barrel and lock parts. I oil up the parts, and reassemble the lock, and I oil up the barrel and re-install it in the stock. 
OH and the lad would've been thrown in the guardhouse or stockade..., the brig is for sailors. 
LD
