Congratulations. As for bullets, to the best of my knowledge the Jungle Gun ammo was identical to the Paradox. Holland&Holland offer a slug round for their Paradox guns, as I understand it it's a mild conservative low pressure low velocity load suitable for vintage guns too. H&H web site also has the instructions on how to tell if their Paradox ammo is OK to use in your gun. A bit expensive, yes, but it's a way to have factory ammo.

Russian Hunting Shotguns