I agree with Cornbush about the Arisaka, but with emphasis on the "highly". No matter what the base, whoever did that was undoubtedly skilled, but with a lot of time on his hands.
More important, if the bolt and receiver were as heavily modified by welding as it appears, there is NO way I would fire that rifle. Nyet. Nein. Non. No.
No one can have any idea what the welding heat did to the original steel or even what the original steel was in the first place. It might, for example, have been an Arisaka, or it might have been a Japanese cast iron training rifle. I don't know and doubt anyone does.