Is This Arisaka 1943 or earlier?

[Aragorn243]

Odd as it seems, we are discussing only one type of Arisaka, the Type 99. Theoretically, the parts are interchangeable throughout the entire series so long as it has that mum stamped on it. It met the standards of the military. Nearly all the changes were made to simplify production without sacrificing function or safety. Later models got rid of the luxuries, were polished less, and used less metal on parts that were not essential to the operation.

I would be a bit concerned in that the bolt was made by a different manufacturer but that in itself may not be all that unusual either. Most people wouldn't know that anyway.

Those that didn't get the mum stamped on them should not be fired, they were probably never intended to be fired. These are training "rifles" or school rifles that were put together to look like a rifle but not function as one.