I'm sure someone can come up with a few negatives, but the only one I can think of in the context of your question is the weight of a 12 ga. Super with 28" bbls for pheasant hunting. I'm guessing this configuration to weigh about 7.5 lbs... which can get heavy walking around with for hours in heavy cover.
I understand. My favorite right now is my 1913 Parker VH 16ga 0 frame 28" bbls all original w/vulcan steel bbls that weighs in at just 6lbs. I've just always wanted a Superposed. I just wish they would have made a 16ga. Lordy, what a grouse/pheasant gun that would have made!
