I don’t know what it is. But I now want one.
Yep that’s it
Is it a shotgun?
Yes it is.
Is the inventor better known for inventing pump actions and his work on cars?
Possibly, I’d never heard of him before finding pictures of the gun in question. He did have patents relating to pump actions along with early work on steam cars and motorcycles.
Me either, but I vaguely remember an episode of forgotten weapons.
Is the guys name roper ?
Yes it is. And over to you.
Looks German in the middle, Swedish at the front and Japanese at the back.
Little bolt handle tells me it might be some sort of .22lr training rifle.
Wrong on all counts, Lol!
Not Japanese?
No although I can see the similarity to my arisaka. 
Maybe it is a custom build for someone with small hand syndrome 
It’s wierd, there is almost no rear reciever. The bolt handle seems to occupy most of it, leaving very little meat. Is it experimental? Did it see regular service in a military?
Yes to it being experimental, but a version of it almost made service in the Commonweath