Very rare looking for any info

[jpoyraz]

Hello, i’m looking for info about this 13,5mm cartridge, the measurements are:
Case length 15 mm
Bullet diámeter 13,5 mm
Overall length 24,1 mm
The headstp is FUSNOT BRUXELLES
thanks

[Aaron]

I’ve seen a handful of these. @Daniel has one too. I don’t know what it was made for though.

[Daniel]

Unfortunately I do not have this unit in my collection. Indeed, there is one unit here at Uruguay in a collection that belongs to J.L Rubio.

This is a section of a old picture, it says 13mm:

Hope I can get it
Daniel