@ArbiterThel68, your thin patches are letting a lot of fouling build up in the bore. If that fouling is not removed by your patches and if they are dry, the fouling is not being removed. It is important to know that the patches will compress to take up the windage. You need some extra thickness to partially fill the grooves. Lubrication softens the fouling in the barrel and the act of compression will push the fouling down the barrel with the patched ball to be shot out. However, there must be something to soften and loosen the fouling. That is not happening with your thin patches. The fouling will build up and by the third to fifth shot, will be so thick in the barrel that loading will be nearly impossible. One must follow a procedure to remove as much fouling as possible between shots.
A dry patch will not clear powder fouling from the bore and the grooves. Very thin patches will not work even if they are lubricated.
There's two ways to control fouling in the barrel.
One method is to wipe the bore with a solvent dampened patch on a slightly undersized jag. The damp patch will slide over fouling with the solvent softening the fouling. The patch will bunch up and pull the fouling out of the barrel. You want a damp patch to leave no dampness to contaminate the powder. Usually, the damp patch is followed by a dry patch. Now, loading can be done with the effort being the same from shot to shot.
The other method is to rely on the next patched ball to push the fouling down the barrel to reside between the ball and the powder charge. This method uses a very wet patch to soften the fouling and sufficient thickness to wipe fouling from the grooves. The dampness helps in the compression of the patch material. Loading following this method will also be the same from shot to shot.
I use 0.018" thick cotton drill for patching. You may want to use 0.015 " pillow ticking patches. My patching material is unlubricated until I load the rifle. Let's keep the lubricant simple. For initial load development, a mix of 50/50 liquid dish soap to water should work well.