MC.
I wasn't going to reply to this one, but I have to to find out what makes you make the statement you made, and maybe I can help you with loading information or your method of fouling control.
There are a very few shooters that will shoot 100 to 125 pounds of powder a year like I do with black powder cartridge rifles using Goex powder in a .40-65, .40-70 ss, .44-90 sbn, 45-70, .45-90. and the .50-90 using regular Goex and Goex express powder.
None of these calibers in my Sharps rifles with 30 to 34" barrels foul even when the barrel is so hot that the screw on the forearm is so hot it burns your hand after shooting a string in a match at temperatures 90 degrees plus in the dry Nebraska and Montana air.
I have used all powder except Wano and not just one or two cans to see how it performs and none will give me the extreme spread in the low single didgits and an SD at 2 to 4, with a 20 shot group using Goex, NONE!
You can PM me if you like if you would like me to help.
Kurt