While searching something else on the PINDAD website (from Indonesia) I found an entry about a caliber I have not heard of before.
It is listed as 7.62x45. The ball round is designated MU11-TJ and the blank as MU11-H.
The assault rife style weapons firing these cartridges are SABARA V1 and SABARA V2. Both are meant to be law enforcement weapons.
(scroll down to lowest entry)
Does anybody have more info on the ammunition? Are better images available? Are any head stamps known?