szihn
I had my 9.3x64 made up about 30 years ago - I think it was a Donnerly? barrel from the States.
Twist rate is 350mm or 13.779486".
Shoots 270gn Speers (light load) at 2100fps, 286gn Woodleighs (Protected point & Solids) at 2630fps & 293gn TUGs right on factory spec of 2570fps - all of which loads are more than accurate enough to do for what it was designed to do - well for me anyway!
None went sideways through the paper & groups were not blown if I did my part, nothing ever got away that I ever shot at!
Accuracy, lets just say my rifle shoots far better than me!
Never tried 320gns, & because the 1st generation hydros (no caps) didn't feed well in my rifle I never continued with testing to see how good they'd go - from memory they shot alright, but never kept the records or notes - sorry!
Will try the 2nd generation ones when I need to as these have protective caps to add feeding!
93x64mm