I've got a 9.3X57 Mod. 46 ,I've worked up to 44 gr.s of IMR 3031 with the 270 Speer ,Try increaseing your IMR 3031 a little at a time, MAX is 45gr.s of IMR 3031 ,I don't have it in print,just Verbal !
I've not had time for serious testing for this round.
My 9.3X57 is 2nd. down in pic.
You got a heck of a rifle..