RobertN
Super Member
That was the common naming, although sometimes it went a little further, ie 45-70-405 was 45 calibre, 70gr black powder, and 405gr bullet. A quick web search show 30-30 was originally 30-30-160, and a year later changed to 30-30-170.
I know most of you know this, but the old designations, e.g., "30-30" indicated the caliber and the grains of black powder, respectively...thus 30-30 meant 30 caliber, 30 grains of black powder. Lots of the old designations out there, like 45/90; 25/20; 45/70, etc.