As a Brit yes I know born on the wrong side of the pond!!! Though I can remember those engineering history lessons at College in the now very dim past about Stevenson Maudsley and IK Brunell including how Bore appertaining to the barrel diameter of a shoulder mounted sporting guns and certain metal pipes came about. And you can say it could only be the Brits who would come up with such a system and the system is based on the British Pound weight. So to make sense of it a four bore was the diameter of one of the four equal spheres of Lead that would weigh exactly one pound then so on for the number of balls in one pound for the eight ten twelve sixteen and twenty. Now that can not be the whole story because it is Brit and there where exceptions such as Swann drops the favourite food of the large bore Blunderbuss and to further complicate matters Newcastle shot and London shot where two entirely different things. It is amassing how we made things work but we did and in the words of one of the lecturers it was all done by trial effort judgement error and a lot of luck!!!
