Well, the Arisaka actions are definitely strong. In his book _Bolt Action Rifles_, Frank de Haas recounts a 1959 _American Rifleman_ article in which a 6.5mm Type 38 was rechambered to .30-06 by an idiot. The problem?...the bore was not rerifled to the larger diameter! At each shot the .308" bullet was swaged down to .264". Yet, even the NRA staff was not able to destroy it.
de Haas suggests that the actions can be rebarreled to any cartridge using the .308 Win/.30-06 rim diameter that will fit in the magazine. He also states that he rechambered 6.5mm Type 38 rifles to take a 6.5mm/.257 Roberts wildcat (pretty close to the modern .260 Remington) and 7.7mm Type 99 rifles to .30-06. He advises that you will likely have to tweak the cartridge guide lips and the feed ramp to insure reliable feeding.
de Haas also warns against getting stuck with the pot metal training rifles, notable by their smooth bores and integrally cast or welded-on tangs.
The Type 99 barrels are threaded at almost 17 tpi over a length of .700" and a diameter of 1.050". Most sources indicate that the receiver threads are hard enough that they will swage the barrel threads into the correct pitch.
The Type 38 barrels are threaded at 14 tpi over a length of .708" and a diameter of 1.025".