Battle,
I have a Birmingham 2" and I love it. Mine weighs 5# even. Light weight is big the attraction for me. I would not buy a 6# 2" gun, at that weight I would go with a 2 1/2".
I do not understand the price differential either, but 1cdog may be right regarding limited supply.
I have not seen any real advantage shooting grouse & woodcock with it over my 20b, or even my 28b, though.
But the Birmingham 2" guns are another interesting example of the gun trade from another time.
I have never regretted buying mine.
