.500 Revolver Round?

Hi Forum,
I got hold of this .500 round, bullet Ø close to 13 mm,
Bullet seems to be Lead
Case lenght 19,45 mm
Rim Ø 14,2 mm

What round is this?

Please, can you post pictures?

Ofcourse Fede! Thank you for reminder. I forgot. Now the pics are present

.500 Revolver, as made by R.W.S.

Thank you Pete!
Not much info to find of this cartridge, but I did find a small note in the pages from IWM with reference to an old book.

I found some more as well: As in .500 Tranter and .500 Webley.

I think @Mel wrote something on these recently?

Yes, I did something on a large-caliber British handgun cartridge but it was the .577 revolver round, a little bit larger than the .500.