Well John, I hate to disagree with you but I still think a good case can be made for the Arrieta 2" gun and here's why. First off let me say that my Wingshooter's Light Game Gun with 27" barrels weighed exactly 5 lbs. 13 ozs. on a dead accurate scale. It's action was smaller than a standard 12, I think it was built on a 16 frame. It was proofed for standard CIP pressures so obviously it could have been made with 2 1/2" chambers but that wouldn't be a good idea because then you have a gun that some fool can stuff 2 3/4" shells into. That's one of the unknowns when you buy a used 2 1/2' chambered gun, has some fool fired a few hundred rounds of SAMI 2 3/4" shells thru it? Most of the time of course, no problem, but with a lightly made gun like the Arrieta two incher it would be a problem. I sold mine several years ago in a moment of silliness but would love to get another and with 25" barrels, Churchill rib and a 14" stock believe that the weight could be held to five and three quarter lbs.
Nial