Thanks for all the info. I think I will settle on a rebore. I think I will go to the 7mm 7/57 seems like a good round
I'm not an expert, but be sure you consider the magazine length of that Arisaka versus the likely loaded length of your 7x57 cartridges. May, at a minimum, need to watch the throat length in the chamber. It all may be OK, but I'm just suggesting you consider this in advance.
