Lately I've been using Rusty Duck Black Powder Solvent with good success. 2 to 4 soaked patches (both sides) worked through the bore followed by 2 to 4 dry patches. Then I run a patch or two of denatured alcohol to dry the bore followed by a patch or two of balistol to confirm a clean bore. If everything looks good at that point I run a couple of dry patches followed by BC sheath for storage. Wipe down the outside and clean the nipple, apply antisieze to the nipple and install. Done. Takes about 10 to 15 min.

There is an adapter that can be screwed in inplace of the nipple that has a piece of tubing that can be placed into a bucket of water. This allows you to pump water in and out of the barrel without removing it from the stock, thus saving that time. I don't have one nor have I used one so someone else will have to comment on how well it works.