As far as I know, Swiss powder sold in the US has the same size grains as the other black powders sold in the US. That is, Swiss 3Fg sold in the US is the same size as GOEX 3Fg.My confusion seems to be in the granulation of swiss vrs goex.
It's when looking at the Swiss powder sold in Europe that things get confusing. The size grading system they use there is (I think) backwards from the size grading system we use.
Someone will correct me if I'm wrong but I think their 1F powder is similar in size to our 4F and their 4Fg is similar to our 1Fg.
They also offer black powder using a 1/2 designation indicating it is half way between the whole number grades.
OK my European friends. What's the right answer?