Hi,
Cool case!
I'm the one called in by Hoeksel, and I agree that this headstamp doesn't look like anything I've seen of Japanese origin, so far...
I may be sticking out my head, and I may be completely wrong, but my gut feeling is that it may be a Chinese case; somehow the Kanji (apart from the numerals (i.e. '5' at the 12 o'clock position, and '7' at the 1 o'clock position), which are the same in both languages) strike me as being Chinese. No standard Japanese headstamp style is used (neither IJA nor IJN), and I do not really agree that the star looks like the typical Japanese army one, as the one displayed on the headstamp (3 times over!) is a pentagram, whereas the IJA stars I've seen were always 5 pointed stars (and I've never seen them on cases anyway), but not pentagrams (i.e. no 'inner lines').
Either way: nothing of the case looks Japanese to me (except for the numerals): the calibre is not known to me (which, however, is not strange for old Japanese cases), the headstamp style looks completely off, same for the primer....
Nonetheless I could be mistaken, of course, and Hoeksel's suggestion is a very interesting one: I've attached pictures of a 1905 'Japanese' case, manufactured by 'Berndorf', and then date-stamped (in proper IJA style!) with proper Meiji date indication. I myself also have a Meiji era case (1904; roughly measuring 76.2x104R -or thereabouts-), which also follows the typical (be it slightly different from the Showa era headstamps) IJA headstamp style. It should be noted that both these cases have a very different, fixed, primer. Also, Japanese primers tended to be stamped. The western '3' on the headstamp is interesting. It is not placed in such a way that it could be a month indicator. Possibly this suggests foreign manufacture...
As for the case itself: the rim diameter mismatch by 3mm might not be of significance (could still be measuring differences), but then again, it may...
A good thing to check (in order to check if the case is cut down), is to check the thickness of the brass at the case mouth: it should normally be pretty thinnish, if it is of proper size, whereas cut down cases tend to have much thicker brass walls at the case 'mouth'. This may not be a definitive check, but it tends to give a very good indication...
Regarding the remarks made by the mentioned person who states that the other specimen dates back to the Russo-Japanese war: this might be true, but it may also be just an assumption made by someone (not very uncommon to come across that phenomenon; it has happened to me on many occasions where things said by people simply couldn't even be true).
A few months ago GI Zhou helped me excellently with some translations of Chinese headstamps. I'm certain he could shed a light on this...
Edit 1: my Meiji era case is described in detail in this thread:
http://www.bocn.co.uk/vbforum/japanese-meiji-era-t45764.html?t=45764 (ever since, I did receive a partial translation of the Kanji that are marked in red, but it wasn't a contextual one, so I'd like to still get that someday)
Edit 2: I just added pictures of both Meiji cases; the first four pictures are all of the Berndorf case (unfortunately not part of my collection), with the following dimensions: 81x230R, with a 95mm rim diameter. The other 5 pictures are of my Osaka manufactured 1904 case, which has a (measured) calibre of approx. 76.2x104R, with a rim diameter of 84mm. Note that both cases feature the 'double rim' type (what's the proper term for this?), just like e.g. a 17Pr case does...
Cheers,
Olafo