I was not aware of the pressure issues with the smaller bore bullet barrels, especially not the way they eat away at the flash hole in the nipple.
I may have to rethink the fast twist Scout Rifle concept, and go back to my original idea which was a .58 caliber × 21" long × 1" octagon × 1-48" twist round ball barrel from Rice, Colerain, or Kelley.
With the bigger hole it would weigh less, and truth be told, I'll in all likelihood keep my shots under 100 yards anyway.
A 277 grain pure lead round ball will kill ANYTHING on the North American continent. All I'll be hunting are deer, black bears, and feral hogs so a long range bullet barrel is kinda a want, not need thing.