"One thing I can tell you is that they had a light machinegun that used the 5rnd rifle stripper clips. I'd have to look in my references to name the type/model but it is known."
That was the Type 11 Light Machine Gun, designed by Kijiro Nambu, and adopted into service in 1922.
As originally designed it was to provide commonality of ammunition with the rifle squad it supported. In theory, that's a great idea. Supply is simplified with everyone using same ammo on the same clips.
In practice, however, the rifle round proved to be too powerful and a special cartridge, the 6.5x50 Genso, was adopted, which was supplied on 5-round stripper clips, just like the rifle ammo.
The feed mechanism, while odd, worked well.
The gun did require lubricated cartridges because Nambu never quite figured out the importance of slower primary extraction so that the case head wouldn't come off, leaving the case body in the chamber. And that lubrication (via a small reservoir on top of the receiver) was an invitation for stoppages due to accumulated dirt and powder fouling.
All in all, however, the gun proved to be quite reliable when kept clean. Otherwise, not a great gun.
There's a LOT of very good information about the gun, its operation, and its ammo here:
http://www.sadefensejournal.com/wp/?p=2868
Included about 2/3rds of the way down the page is a REALLY neat photo of an ammo case containing 24 5-round stripper clips.