Steve - I ran re-sized 300gr., but RN's, mind you, at 2,170fps with sub-1" at 100 meters - for 5 shots, from a 1929 model 46 Husky, 9.3x57 with 3-9X Bushnell 3200. That rifle has a 14" twist, which was also the common twist for most .35's IIRC, back to those days.

Pretty sure that 12" would shoot EVERYTHING you are likely to load - to 350gr. at least.