The the "JS" bore guns were 8mm, not the 7's. And the 91 Argentine isn't a 7 or 8mm, it's 7.65x53 using .311 bullets. Back in the day it was loaded and chambered in the Winchester 54 and Remingtons Enfield based bolt gun- Model 30? Anyway it was pretty popular. That was in the 30's I believe. After WW2 about the only ammo you could get until the late 90's at least was Norma, maybe CIL. The Norma stuff was HOT, real hot. 150's were up past what would become 308 levels and chasing the '06. There wasn't enough difference in factory loads to be notice by game in the mid weights. The '06's larger capacity showed above 150 grs, although the 215's loaded in the Argie were certainly nothing to sneeze at.
My comment on the 91 being so much stronger was meant in jest. It's not that it's any stronger than a 98, it's probably not since the design on the 98 is a later development. But Normas views on consumer products differed wildly from US ammunition makers views. The underloaded 7x57 US ammo goes back to the Remington Rolling Blocks in 7x57 IIRC. I used one for a few years. "Smokeless action" or not, it had a 20" barrel and the ammo supplied to me as a 15 year old kid was handloads of unknown origin and Norma factory loads. This was also back in the days when hearing protection was for sissies. The fact I can hear anything and can grow any facial hair after the fireballs that Roller produced is surely a miracle!