I tend to agree with Jim W. that if you are going to reload anyway, why not just buy some Norma ammo, and reload the 6.5 Jap. It is capable of some pretty good performance when loaded hotter than the military round (though it can't match the 6.5x55), and you can load it hot in the Arisaka action.
It is a puzzle why the Japanese produced one of the world's strongest rifles, and then used one of the world's most anemic cartridges in it.
Jim