Raimey,
I believe the 3707-fps velocity was for the rimless version, and the rimmed version was advertised at 3400 + (I didn't take time to look it up, but it doesn't make much difference, I don't recall anyone getting that with a chronograph). As I recall, I got around 3250fps with the bumped up 80 grain bullets. I didn't feel confident enough to go beyond that, I didn't want to lose the rifle. I used 4350, I don't know much about Vihtavuori powders. If I had to do it again, I think I would find someone with a ballistics program to run it. If the program didn't include the max pressure for 5.6x61R, I would use the one for 7x65R which I believe was 46500 psi CUP. When you said you have proper brass, do you mean original factory cases. If so, do you have Berdan primers also? If you find out the Rottweil powder was R5, that will give us something else to go on. I think they stopped loading the ammo in the early 70s, I can remember Waffen Frankonia having some "in stock" while I was there the first time, but I didn't have the rifle then. By then to be legal for large game the cartridges not only had to meet energy requirements (1440 fp) but also had to be 6.5mm.
Mike
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