Ger,
The 70 in 45-70(an old American cartridge from 1873)doesn't stand for the case length, as the 60 in 11.5x60 does. The 70 stands for 70 grains of black powder, which was the original load. The 45-70 case length is close to 51mm. The rim is flat, unlike the rim on 11.15x60 or any other cartridge based on that case( Mauser base MB) The 45-70 has a slightly larger diameter bullet(.458")and rim diameter(.600"), but because of manufacturing tolerances may go into a 11.5x52R chamber. It would have a few thousandths excess headspace, because the rim is thinner than the MB rim. MB cartridges were used in Austria, but were not as popular as they were in Germany. The 45-70 case is .010-.016" smaller diameter at the head, but will expand on firing to fit the chamber. I modify the rims of 45-70 cases to MB configuration to use in my 11.15x51R and a friend does the same for his 11.5x52R. Cases can be made for 11.15x60R from 45-90(again, capacity, not length),because the head and rim are the same as 45-70.
Mike
