I know a little about the 6mm American, they are similar, but I am referring to the 7mm international made by necking down 30-30 brass and fireforming. The American was being pushed about the same time the PPC was gaining ground, but was outclassed by the PPC. My neighbor shoots the 7 international in a contender barrel. Fun little round to play with other than having to control headspace with a false shoulder with first firing. I bought the barrel for him on classifieds in excchange for some tractor work. He had a little problem forming cases, primers backing out a little on first firing.
I have heard rumors that the guy who was initially campaigning the 6mm american was using a hydrolic press to size the case head down to create small rifle primer pocets, but cannot remember the whole story.
7mm International Rimmed