What is this round?

On our trip to Italy in May we found this on the Cavendish Road near Monte Cassino.
It has an odd dome-shaped percussion cap.
Had no luck IDing it on WW2Talk so thought I'd ask here.
What is it & why the odd percussion cap?

 

a picture would be nice


Cheers...

 

I can see one, pasted in below my text.
Hold on I'll post it another way.

 

Sorry Jack, I haven't got another picture of it, one of the other lads on the trip took it.
I'll ask if they have anymore.

 

The date appears to be 1940. The "DI" designation was used by ammo firms in four different countries, according to my records: Canada, India, France and Germany.

 

Does this help?

 

It doesn't look like a cartridge case at all - most probably an artillery primer.