The 7x64 is usually made with a fast twist, normal for the heavy bullets commonly used in the cartridge. My BRNO twist rate is 1:8.75. I believe the Mannlicher is 1:8.6 Sako is slower at 1:10. I found them all to shoot 160-175 grain bullets best, except an odd RWS load with the 123 gr cone point. The cartridge is made for a standard chamber with a long throat and a fast twist barrel, to accommodate the long heavy bullets that European hunters prefer. ( me too) If I was to pick one load for the 7x64, i would choose 16o gr Nosler Partition or Accubond and IMR 4831 powder for a load that gives a muzzle velocity of 2850 fps. But the 175 grain loads are excellent, except for the Remington, it is crap in every rifle I have
shot it in.