I recently acquired a arisaka rifle and not knowing much about these long guns, I took it to a local gunsmith who poured some gel into the chamber and once it hardened spec it out. He gave me a brief history on them and told me the caliber of this particular rifle was 6.5x50. So like a kid with a new toy, I can’t wait to field test it but first it’s off to the sport shop I go for a box of ammo. Strangely enough, no one at the sport shop had ever heard of a 6.5x50. Only 6.5x55, 6.5 Swedish, etc. So I decided to research this myself as much as possible online but end up more confused than what I started. On a few forums that I came across one guy says that the 6.5x50 is the same as 6.5 Jap. Sounds likely to me, after all, arisaka is Japanese. Another states that a standard .264 win is the same and yet another fellow claims that it’s a .256 cal. Anyone have any thoughts on the subject.