8x50R or 8x56R Siamese Mauser?

[ckcadavona]

A friend of mine recently a5cquired a Siamese Mauser. The seller told him it was a 1903 chambered in 8x50R. Is there a way to confirm this without taking a casting of the chamber? I've read there would be some grinding around the rear sight if it was an 8x52R chambered rifle. Would this have been reblued?

In the following pictures the side of the rear sight base looks like it could have been ground and reblued but I'm nut sure exactly what to look for. Can anyone confirm this using these pictures?




Bonus pics in case anyone can read Thai.





The bore seems to be in excellent condition but there's dark spots at the beginning of the rifling that none of my other milsurp rifles have or at least they aren't as noticeable. Is this normal?



Another note worth mentioning is the trigger pull. The trigger pull on this rifle is much better then my K98 and on the same level as my K31 and M39.

Thanks

[SciFiJim]

I blew up the picture of the bore and it looks like the rifling doesn't start at the beginning of the barrel but instead starts a little ways in and is sharp edged instead of gradual. If so, I would thing that it would tend to catch and strip lead off of a boolit.

[elk hunter]

The ground rear sight base indicates that your rifle has been rechambered from the original 8 x 50 R to the type 66, 8 x 52 R cartridge. Cases can be made from 45-70.

[3006guns]

...........and whatever you do, DON'T allow your friend to get ideas of making a .45-70 "sporter" out of it! Siamese Mausers (actually manufactured by the Japanese) in original condition are getting DARN hard to find. I've collected Japanese firearms for many years now and also have a full military Siamese, but it's not that nice. That one looks like an excellent example, with sharp markings, etc.........so don't let him take it apart or modify it! Some collecter will thank him years from now.

These rifles were made on contract in the Japanese aresenals, right alongside of Arisaka production from what I can find out. They are an almost direct, unabashed copy of the Mauser 98 and are made of excellent steels and heat treating.

That stamping on the side of the receiver rail that looks like a flower petal is actually a representation of piled cannon balls. That's the standard aresenal mark for the early Arisakas. At some point in the 1920's (after your gun was made) operations were transferred to Tokyo and they continued using the same marking.