Never had any problems with the #13 unless I used to much of the stuff. If you know you did you can cure it quick with shooting a cap another dry patch and a nipple picking. One thing I have done for years but not lately is actually clean my rifles with #13 instead of the hot water in the sink stink thing and it worked fine. Wife was happy I was doing it too....

Course fouling seems to hold up my sabots more than anything the last inch or two being the worst. I find that if I am on the range shooting a wet followed by two dry cleaning works quite well. Some of the sabots load hard always have always will. I now buy sabots in bulk and use pistol bullets that are the right size for them.

Another though is whatever you are loading may be making some hard fouling and a pass or two with the brush may help. It never hurts.