fffg: If you use a corn meal filler between your powder charge and the patched round ball, the meal should help scour out the crud as well as seal the gases behind the patching so you don't get blown patches and cut balls to destroy accuracy. Other shooter routinely run a rod with a good brush down the barrel after each shot, so that the crud does not have a chance to build up. harddog is correct in saying that the crud will destroy accuracy for you because it forces the ball to be positioned differently from shot to shot, changing the amount of space for the powder to burn in each consecutive shot. I use Wonder lube 1000, because it does soften the crud so well that cleaning between shots is not usually needed, except in the cold dry winters here in Illinois. I also lube a cleaning patch and run it down the barrel after seating the ball to lube the barrel in front of the ball, and put lube on any crud that was not loosened when I ran my brush down the barrel after the last shot. Using a chronograph, these practices produce much lower standard deviations in velocity for any given load, and the accuracy of the load rises. In cold weather- really cold weather- you can expect velocities to drop 10 percent or more as it is. When hunting you leave the patch and ball in the barrel for hours, if not days, You want a good lube in that patch so that the patch does not draw moisture and rust the barrel where the patch contacts the bore. That corn mean used as a filler under the ball will absorb any moisture that may get down the barrel, and keep it away from the powder charge. In cold, wet, weather, keep a feather or toothpick in the touchhole to keep moisture out of the powder charge.