When you speak of plastic, and stainless steel, and scopes in the same sentence you speak of black powder firearms, you are just talking about a cheatline. It isnt a real muzzleloader, and it isnt going to be used for traditional muzzle loader purposes. It is just an excuse to get another game tag. Once you go to synthetic powder and copper jacketed pistol bullets in plastic sleeves, you might as well just take a .30-30 and be done with it. There isnt any pride left in that.
Whoever it was that spoke about flintlocks not being accurate or dependable obviously didnt know squat about what they were telling you. I do not use flinters, because I am a fan of the Hawken era, but they shoot just as hard and just as accurate as any other rifle. Once you blow a hole though both sides of an animal, how much more do you need? I use percussion rifles and patched round ball. That is what the traditional muzzle loading rifle was designed to use. Thank God, Colorado just outlawed that CVA electronic ignition and scopes.