Pardon my ignorance, but what is swabbing between shots?
It has long been thought, the way to the best possible accuracy with a black powder rifle is to keep all things equal. For instances, if you measure your load then you measure the same each time. The same bullet and sabot, same cap, even as close to the same loading pressure when you seat the projectile. So in order to keep all things equal, many people swab the barrel free of the major fowling, between shots.
Take a patch and dampen (not saturate) it with alcohol and car windshield washer fluid in a 50/50 mix. Some use Windex, spit, and all other kinds of swabbing solution. I prefer the first mentioned mix. Work that patch is short strokes from the muzzle to the breech. Pull the patch back out and then flip the patch and swab it in the same manner again. This will pull the fowling from the powder out of the bore. Some powders fowl worse then other. Then swab the bore with two dry patches in the same manner. You now have a relatively clean dry bore identical shot to shot we hope when you shoot. This means the projectile, powder, etc should act the same shot to shot giving you better consistency and accuracy.
That is swabbing the barrel...