Hi, I was surfing around looking for information on a Japanese arisaka type 38 that I inherited from my grandfather when I stumbled upon this thread. He got it from a dead soldier in WWII as well.
I found this page:
http://www.radix.net/~bbrown/japanese_markings.html
It has been a wealth of information. On the lower lefthand side of the chamber, on the outside, there should be a serial number. With that number and the other symbols on your rifle, you should be able to pin down approximately when it was made, and which arsenal/subcontractor made it.
Below is a brief summary of what I have gathered about this rifle:
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A chrysanthemum with 16 petals (the symbol of the Japanese Emperor) was usually stamped on the receiver of rifles manufactured for the Imperial Japanese Army, indicating that the rifle belonged to the Emperor. The chrysanthemum was at least partially ground off of all rifles which were surrendered after the war, apparently as a face-saving gesture. Rifles captured in the field, however, normally have the chrysanthemum symbol intact.
The Arisaka Type 38 is chambered for 6.5mm semi-rimmed case, which is no longer available. According to the ballistics table, the Type 38 fires a 145 grain bullet at 2400 fps...more than enough to kill a man, deer, bear, etc.
6.5 Japanese Arisaka
The Japanese army adopted this chambering in 1897 but the rifle in which it was originally chambered was proven unsafe. That gun was replaced in 1905 with the Model 38 Arisaka, which has proven to be one of the strongest guns ever adopted by any government for military use.
The European designation, 6.5x50R, indicates that this is a (semi) rimmed case and that it is also the shortest of the many 6.5mm military chamberings, all dating from the end of the 19th century. Limited powder capacity results in somewhat limited ballistic potential for this chambering. However, since the action of the Arisaka is so strong, this case can be loaded to its full potential. This allows this diminutive case to produce surprising ballistics and it is a very good choice for use on lesser to medium-sized game animals. Currently, Norma is the sole producer of cases for this chambering.
Ammo:
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=719230
My Rifle:
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Type 38 Japanese Arisaka Calvary Carbine Rifle of World War II
Taken in the field
Manufactured by Nagoya Arsenal - ca.1933-ca.1940
Series 26 - 82,873 of 99,999
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You should probably find a local shop that that can appraise this for you and give you some advise on care.