Hi guys,
I'm kinda back (in and out) to this forum, after having had about two months of time that were too much filled with work obligations, and hence too little time for fun stuff like this.
Anyway, most of what I can tell about these items has already been answered in detail by the rest, but some points of interest (perhaps):
AFAIK these projectiles are completely wrong for them, as they appear to be Hotchkiss projectiles, as stated, of French manufacture. I can't say for sure if these projectiles were perhaps manufactured for Japanese Hotchkiss rounds, as there's little or no documentation out there on ammo from before the Showa eras, however, from what I've seen, including in Ken Elks' part 2 on Japanese ammunition (page 190), it doesn't seem likely.
It appears that only the IJN used the 37mm Hotckisses, and the types shown look very different (with a very wide driving band) and have naval (anchor shaped) acceptance marks. No mention whatsoever of French manufacture...
Some of the Japanese ones are shown right here on BOCN too, in the thread:
http://www.bocn.co.uk/vbforum/japanese-hotchkiss-37mm-t37127.html?t=37127
It looks like they're standard (?) 37mm Hotchkiss projectiles, and they're definitely put into the wrong case. This type op Japanese 37mm case was equipped with standard 37mm projectiles (at least: that's what my documentation says). The Hotchkiss projectiles are also MUCH older than the cases.
As for the markings on the projectiles; the '+' like marking look familiar: I've seen similar markings on some Russian cases I have at home. Also, I have two 76.2x385R 'Ratsch-bum' cases with very bizarre headstamps: they look essentially Russian, but they also feature the notorious 'F' marking and the crossed cannons of the Osaka arsenal. Japanese manufacture for Russia? Vice versa?
Anyway, one of these cases also has this + resembling mark.
I wonder what it means....
Cheers,
Olaf