Wild Guess sort of...but since reading up on and trying to get into clay shoot...sport shooting if Im correct is more a thing in europe vs here........7/8 is usually used in clay and sport shootings and Iam guessing from what I read that is why?! We think of it as....what can I hunt with 7/8....its a sporting shot load and again I think they do more sport shooting over there from what I understand vs here...
Good question and if im wrong id be interested in the right answer as well???
I am not sure why either. Back when our family and I was very young my father did 1 1/8th oz loads of #8 shot for Trap. They were of average kick but dusted targets. He was introduced to #9 shot and cut loads to 1oz. That made a remarkable difference.