Crow Feather,
I was wondering as to the diameter of the bullet type and diameter. You only said it was 540 grain. Were the bullets swagged, cast, tapered, straight and of course diameter? I as this as I am considering p-p for my 40-65 sharps. I have been doing lots of reading about bore-size p-p bullets, under-size, groove-size, groove-size +. All this can be overwhelming, and as you have provided us with the nice picture and your load data just one more thing would help.
Thanks