Just wanted to say that since it is a 6.5mm, then it is probably a Type 38, which was produced prior to WWII, going back to the turn of the century. It is much higher quality than the later Type 99. So there probably ain't nothing wrong with it in that respect. I had a sporterized 38 with mum intact, lyman receiver sights with target front sight, and some old 60s looking semi-inlet-type stock that had surprisingly(from my research) had not been re-chambered from its original 6.5x50r. Turns out it should have been. It was actually accurate but ate brass up. They lumped up predictable near the base every time, which I found out was a common trait among these rifles because they had slightly loose chambers for tropical conditions. I doubt the Japs cared to save brass for reloading, so it was really of no concern to them, just to me, a broke college student who has to reload in order to shoot enough. I sold it last year to a collector at a gun show because it still had the mum.
In my research, though, I found out that most of the re-chambers were to 6.5x .257 Roberts. While I can't confirm this for sure, it seems like some just straight up shot .257 Roberts in their guns. After all, true 6.5mm is .257 bore diameter. But there is a difference between a .25 cal and a .26 cal. Of more interest to this discussion, I also found out that there are two different but very similar cartridges. There is an actual
6.5x57mm, which dates to the late 1800's and is still in use in Europe. Then there is the 6.5x .257 Roberts, an American wildcat of another wildcat invented for rechambering Arisakas so brass could be found.
While they are both based on the 7x57, they are not both simple necked down 7x57s. The actual 6.5x57 had a different shoulder angle, i.e. it is not a simple necked down 7x57. The .257 is, and therefore a true 6.5x.257 would be also. Maybe you should investigate this route and see what you actually have. If you don't believe me, look at Norma's website. Even the 8x57 anid 7x57 have different angles. They don't show 6.5x57 but I'm making the point that not all x57 standards are strait neckdowns.
Actually while typing this I felt I need more substantiation, so I searched for a while until I finally found this drawing of 6.5x57
http://www.ballisticstudies.com/Knowledge+Base/6.5x57.html As you can see the neck angle is about 2 degree difference between the two rounds. You should probably check up on this as you may actually have a gun chambered with a real 6.5x57mm reamer.
Sorry for the long post which may not even have what you need, but I wanted to share that with you.
