The Nambus are different. Nothing "typical" about them.
I still have a few boxes of Midway cartridges, which function as well as any postwar commercial ammo, and better than most. It most closely resembles the original Japanese service round-- all examples of which are now as dead as Hirohito-- but not exactly. The Nambu is particularly sensitive to dimensional and ballistic variations in ammo, so reliability is not a strong point. But they are very pleasant to shoot, with excellent sights and a fine trigger pull.
However, don't have a stoppage; with no manual slide lock and no last-round holdopen except the magazine follower (which makes magazine-changing a struggle), clearing feed jams takes three hands and a trained monkey.
There is hope: Starline recently made a production run of new Boxer brass cases for reloading. I bought a thousand; now I need to find bullets and a fastidious reloader.
Correction: I was confused. The Starline brass was NOT for 8mm Nambu but rather for another "Ammo Orphan", the French SACM Mle. 1935-A in 7.65mm Long.
Years ago I toyed with the idea of rebarreling a matching but externally "brown" Nambu to 7.65mm Parabellum, so as to shoot more readily available ammunition. It would have involved some serious gunsmithing, as the original barrel is integral with the recoiling barrel extension in which the bolt reciprocates. The barrel would have to be cut off at the shoulder and the extension bored out and threaded to accept another barrel (I have one, a postwar barrel for a 7.65mm Mauser Luger). But then shortening and recutting the chamber end of the Luger barrel would require rechambering it, which in turn would require a special-order reamer, etc., etc., etc. Then maybe adjustments to the bolt face, extractor, ejector, and so on. You get the idea...
In the meantime even doggy Nambus (and Luger barrels) became valuable enough to discourage such fanciful conversions --which in the end might or might not prove satisfactory. Though reliable figures are lacking, the chamber pressures associated with 8mm Nambu are probably somewhat lower than for 7.65 Para; the Nambu's locking system appears adequate but whether the resulting velocity of the recoiling mass would necessitate greater weight or heavier springs can't be known without empirical testing.