Six-five Arisaka is a dandy little cartridge all on its own, friend.
It has enough power to drop Bambi in his tracks, very little recoil and it is EXCELLENT in brush, likely as good as any other cartridge out there. Its performance is very little under that of the legendary 6.5 Mannlicher-Schoenuer.
Currently, I am handloading for the Carcano, the MS, the Arisaka and the Swede and it is really nice, being able to load a whole bunch of different rounds with a single batch of components and four different buckets of brass!
Arisakas have METFORD rifling in them: segmental rather than sharp-cornered lands and grooves. And it has only 4 grooves, so the muzzle can look as if the thing is rifled with a rounded-square bore and the rifling can look "shot out" and still perform well.
The grooves, however, tend to be quite deep and this asks the bullet to do a lot of deformation in order to get down the barrel. For this reason, I load the Arisaka with flatbased bullets with SOFT jackets. I did try hard-jacket BT Match bullets once but they gave me a 200-yard group that measured 20 feet high and 30 feet wide. The hard-jacket bullets were literally exploding about 15 or 20 feet from the muzzle........ and this is a rifle which groups 4 on a NICKEL at 145 yards when it is fed what it likes.
Nothing wrong with an Arisaka.
If it were mine, I would keep it the way it is, save my money and then pick up a nice 96 Swede to go with it.
Trade-Ex has everything you need to load it, including brand-new Partizan brass which takes our primers.
Hope this helps.