A couple things cause patches to look like that... hot powder, ruff bore, and old patches. The pre lubed patches with age will cause the fibers to weaken and when you shoot them they will look just like what you have.

I would shoot Pyrodex RS, maybe lapp the bore or at least check it, and get some 100% cotton pillow tick from Wal Mart... lube that tick with some bore butter, and shoot them roundball again. Start with 70 grains. At 25 yards there should just be the center blow out of that target.