Help identifying carts

Hi there, I was given a model gun saa and a tin of rounds (only 2 of which are for the gun) the other weekend.
The rest, and there are a number are all solid single piece rounds but the holes at the top all appear to be smaller than 5mm (closer to 4mm) Are they just dummy rounds that someone has drilled the holes into? they don't look like that's the case. Any ideas?

Really hard to say, i have some old models but none take rounds like this. I think there might of been a 4mm cap but i wont swear on that and maybe you put the old paper cap in the end of these. maybe they take nothing and just have holes in for no reason. i will have another look through old rounds see if i have anything similar, but i think our friends in Japan will have to help on this one.

These are most likely cartridges for older non-blowback cap-firing models.

They use paper caps (like claymore wrote) that you put inside the hole. Upon firing the cartridge is pushed onto a pin and cap ignites producing bang/sparks/smoke like other toy cap-guns. However there is no blowback (no energy is used to move anything) and pistol has to be manually cocked to fire the next cartridge.

Plastic caps are a later invention on the road to blowback models.

Your cartridges are typically used as just dummy rounds nowadays.
If you don't need them, I'm sure there will be interested people here :-)

Thanks. John @pfcg reckons they are dummy rounds for old PFC's where the hole at the front goes over the detonating pin to keep them in place at the right distance in the chamber. I have no use for them and quite a few if anyone is interested and wants to make an offer

I have some old non firing models all revolvers but no idea if any of these would fit, got nothing to compare with which is a pity.