Welcome to the forum, Smokeydog. With flintlocks, smoothbores or rifles, accuracy depends on the shooter more than on the equipment. For my part, I consider my smoothbore limit to be 50 to 60 yards; and I have a rear sight on my smoothbore. I've only killed one deer with my smoothie but it was a running shot so I'm satisfied.
Like any firearm you'll have to develop a load the gun shoots well. While I've fired 8 shot groups at 50 yards well under 3", a paper plate size group is all I really need. It is quite possible to have a smoothie shoot as well as a rifle at 50 yards and beyond. If you do well with a bow then you can do much better with a well fed smoothie. Just remember that we're talking "woods" ranges and not bean field distances.