I deer hunt with the traditional Hawken muzzle loader, black powder, and patched ball, and I swab the barrel with hot (HOT) water and it does work really well. To me, the secret is hot water and a good suction to draw the water through the nipple and up the barrel. I have no doubt it would work on shells if you could replicate that type cleaning action. I also us a light coating of high grade gun oil on a final swab, and around the nipple area if I am storing the firearm for even 24 hours. Have to remember to swab again to remove oil, and dry the nipple area thoroughly before shooting again. I've done this with one T/C Hawken since 1986 with no problems.