Recently purchased 40-60 Winchester Hi-Wall manufactured in 1890 according to my Cody Letter. 
Purchased box of black powder shells from Buffalo Arms and proceeded to the range yesterday. I was not expecting great results as the barrel looked rough. First four shots had 2 and 2 less then 1 inch apart however the two groups were 6 inch apart. The more I shot the worse the spread became. Came home and really worked on cleaning the barrel, plugged the barrel multiple time and filled it with boiling water and was shocked with amount of dark thick water which drained out. The outcome is the bore is diffently pitted but a lot better shape than i expected.
Here's my reloading question to start with 19-20 grains of 4198 and .401 lubed (Baffalo Arms Bullet) or does have any experience and would like to make any suggestions?

Thank you

I have an original Ballard Pacific in 40-85 that I used smokeless in as I am too lazy to clean the brass after firing with the holy black.  I decided to try black one day and my groups shrank instantly.  I use bullets cast at 0.410 and size them down to .409 as I recall so that they are a snug finger fit in an unsized case.  I shoot a duplex load to help with fouling as I am a hunter more than a target shooter and wanted to be able to shoot 5 shots without cleaning before accuracy went south.  Black might be worth a try after you get the bore as clean as you can.  Tom