Help with older cart identification.

Hi all.

Along with model guns I collect cartridges (inert, being in the UK). I picked up a varied collection today, and there were a few ‘dummies’ included. One of them struck me as being a possible candidate for a tanio action PPK that I have (with no carts). Lo and behold, it fits, cycles & ejects (I’ve not tried with a cap *edit and fires caps!). So I’m guessing it’s either the proper cart, or I’m just lucky.

The question then, for you knowledgeable folk:

Is this an example of the original cart (smallest in the pics)? And can anyone identify the other ‘dummies’?

Not an easy one mate, i have some rounds that look like they should fire but i cannot figure out how and neither do our japanese contacts. i also have a number of odd rounds and i wonder if they were for early none fire models, like mgc revolvers.

The last one should be the original Tanio PPK cartridge, I have a similar one. It is a cap-firing (sound&sparks), but not blow-back (slide moves) cartridge.
The middle ones seems to be of a similar cap-firing type. I do not recognize them from the photos I have - only seen dummyies with a rounded nose/no hole (for example MGC ones had a lead tip for "real" look) or cap-firing ones that are more cylindrical (top is flat, not rounded). probably from an early CMC revolver. Later thee cartridges changed to multi-piece design.
Hopefully someone familiar with these in practice might be able to help more.