I have seen a few ways to do it.

One is pretty much wrapping your bore brush with a patch and doing the 200 stroke method.

I have seen where you can shoot maxi-ball type projectiles and clean with J-B every few shots. I'm sure you could also shoot PRBs with some JB paste on the patch, but a PRB in a sabot gun you will want to load much lower powder volume, like 60 grains.

What I have read is that you should not use a staight copper brush when doing this method. I'm not the expert on this, but I have read quite a bit on it. Evidently copper brushes will leave copper in the barrel when your using JB paste. You can wrap a bore brush with ticking or a patch or two to avoid this. I'm sure some fine steel wool would only help polish it up much faster.

DO NOT stick one end of your ramrod into a power drill and try to shortcut this method. This will probably ruin your barrell. You want the ramrod end to follow the rifleing groves as much as possible.