I am soon to have time to finish and assemble the fodder for a 6.5 X 257 Roberts rifle and bullets. In the 5 year process of collecting, I acquired a couple of Old reloading manuals that have that particular cartridge listed. This being my first 6.5, It would seem, the 6.5 mm bullet has changed from .263 in Speer 1966 manual, to now, @ .264. Seems unlikely the 6.5 mm has grown in size as it has grown old. One thousandths of an inch seems extreme in bullet talk to me. Especially for a jacketed. It makes a heck of a difference to my 45 Colt. I will slug the barrel. But... If .264 is the only offering for sale, what might be my options? Or, for the converted Jap rifle, do I dwell on it at all? Care to opine?