I have a TK-2000 and a White Thunder, both guns shoot the best patterns with #5 shot. Better than both #4's and #6's. Don't know why, but that is the way it is.
I have never tried it, but if you removed the screw on choke, and covered the external threads on the barrel with something like duct tape to keep them from damage. you might get a round ball to shoot out of one??? You have that long expansion chamber before it leaves the barrel to go through though.
I do know that Knight did not recommend shooting a ball or slug from the gun at one time, and probably haven't changed there stance, even though they have changed hands?
The Knight will rock you with a max load, FOR SURE!