I have a TC Seneca that was originally .45 cal. When I got it the bore was seriously pitted so I had it reamed to .50, as large as I felt safe with considering the outside diameter of the barrel and the dovetail cuts and screw holes in it. I've fired it a few times with 60 grains of powder, #4 shot, and round balls. It's more accurate now with .470 round balls and no rifling than it was with a rifled bore. Patterns with 7/8 oz. of shot are acceptable at 30 yds for rabbits, and grouse sized birds. I'd think nothing of attempting a shot at a deer out to about 50 or so yards. Some think that's too short for practical hunting, but in the area I've learned to like, fifty feet is a loooong shot.
Three Hawks