I load for an older drilling but it is 8X57JRS (.323 bullet). I use a 125 grain Spitzer soft point pushed by 50 Grains of Winchester 748 and standard large rifle primers.

I know the bore is about 0.005" larger than yours but his load develops about 33,000CUP which is on the low end and makes a good White Tail round.

Enjoy the gun...

Don