RGS022,

Mine is a 16x9.3 cape gun, circa 1912, 6 3/4lbs and with almost identical engraving to yours. The answer to your question concerning receiver size is yes they are quite dainty in width but not length. As per "Lock, Stock and Barrel", hammerguns allow for a very narrow action bar. I have another 16ga. that is 5 1/2lbs and it is approximately .2" wider. Wonderful guns.