1903 Mauser type 45 siamese contract

Hi,
I first post in the Japanese section but I beleive this thread belong in here since its a Mauser rifle..

I just acquired this nice Japanese Type 45 Mauser Siamese contract and I am not sure what is the appropriate ammo fit to it ? I read this rifle was originally chambered in 8x50r and later re chambered in 8x52r. How I can know ? The guy who sold the rifle to never fired it and told me its a 8mm.
Any inputs is welcome. Thanks

https://www.milsurps.com/images/impo...35c359dd-1.jpg
https://www.milsurps.com/images/impo...3d74d3b3-1.jpg
https://www.milsurps.com/images/impo...3e52d8bd-1.jpg
https://www.milsurps.com/images/impo...ec5a89dc-1.jpg
https://www.milsurps.com/images/impo...a164b7cd-1.jpg

The easiest way to tell if the rifle has been converted to 8x52R is to look at the rear sight base. The graduations were marked on the side of the sight ramp for the original 8x50R cartridge. When these rifles were re-chambered, the rear sight base had to be re-contoured (ground-down) to match the flatter trajectory of the 8x52R projectile. The old numerals were often cut in half by the grinder removing metal. Therefore, if the numerals on the sight base are partly missing (going right off the edge of the ramp) then 99% chance it has been re-chambered for 8x52mmR.

A beautiful rifle, and it's awesome that you have a correct bayonet for it.

One of my buddies married a very nice Thai lady. He says you can still run into those bolt actions in Thailand.