shotguns
I have a 20ga pedersoli,and a 10ga.For the 20 use a 45-70 case and load equal volumes of powder and shot,10ga use 1 1/4 oz measure.There is a fine article by V.M. Star,aka Mr Shotgun on the dos and don'ts of muzzleloaders.
For shotgun wads[fiber],I've been using 1000+ and olive oil[sweet oil]at 50/50,coating the wads but not soaking to the point of saturation.
Keep nipples clean and dry,when hunting use the hottest cap you have,ie cci magnum [my choice].I even charge the nipples with a nipple charger[fffg],positive ignition is the goal,and then you can play with shot wt and wads if you don't like the pattern.
I also shoot an 1886 model hammerless Elsie[lcsmith] with black powder loads.Plastic hulls can be used about twice before burning holes in the hulls,Recycling freebies [cheap] from the trap clubs work well here.I cut off the crimp and use cards and felt wads. Plastic wads Especially trap wads will leave plastic in your barrels unless you use a card under plastic.
I'm making my shot with a littleton shotmaker,from wheel weights [while they last].Good luck