I shoot the Mosin 91/30 sporter I modded at 600 yards regularly.
It takes the exact same accuracy load as our .308...
In the .308, we use the 175 grain SMK over 43.5 grains of Varget.
In the 7.62 x 54R, it's the 174 grain SMK (in .311) over the same load.
I prefer the "extreme" powders like Varget, H4350 because they are unaffected by temperature.