ORIGINAL: Breechplug
Most all ML manufacrures recommended running a patch down the bore after every shot. This is for compareable accuracy and to keep the barrel clean of fowling and (preventing) the (crud ring) Some powders may have less, some more. But remember were shooting ML's and with this comes extra cleaning of the barrel to prevent the adverse affects of blackpowder or subsitutes,Swab between each shot and you should be fine. BP
Western who makes Blackhorn 209 says not to wipe between shot that you get better accuracy if you do not.
What I have to do when I use 777 can not be call wiping I have to soak the crud ring and clean it out little by little. Lee