Only way to get them spotlessly clean, is to take the barrel off the stock and dunk the breech end in a conainter of water. I use a 2-quart stainless bucket I bought at Princess Auto. An empty plastic Folgers coffee can works just about as well.
A folded wet flannellette patch is wet then placed over the muzzle, then a jag of the appropriate size is centred on that folded patch and this shoved to the breech, then pulled up to the muzzle so water is sucked into the bore (through empty nipple seat or vent), once the water it up to the patched jag at the muzzle, the whole works is shoved down with force, blasting water and crud out of the barrel - repeat about 20 times and the barrel is clean and they water is slightly greyish in colour. If it is black, you ball and patch combination sucks - is too loose. The only fouling buildup that should be in the bore, is that in the breech or patent breech area where the patched ball does not clean it when is is loaded.
After pulling the patch out of the bore, the barrel is dried with a towel, then dry- patched out - usually takes 4 or maybe 5 patched to dry the bore. The last couple patches should be harder to pull our then really hard to withdraw from the now bone-dry bore. I then liberally spray WD40 down the bore until it runs out the vent or nipple seat, then run a doubled clean patch down the bore, blasting excess WD40 out the vent or nipple seat- run that patch up and down several times, then pull it out and use it to wipe down the outside of the bore.
Thus - to "properly" (for me) clean a barrel, takes 5 or 6 patches only - which are reusable if you want. Thus, due to the flushing action of the water, the breech area, no matter what type, is clean and dry, with the WD40 blasting out any residual moisture. Works for US.