I just came across the image below where accidentally a 25x137 round made it into the picture.
By now I know that it is designated “ALR Cinetique” - some sort of “kinetic” cartridge.
Maybe something for driving or propelling or for creating some sort of kinetic impulse.
The latest NEXTER catalog (2016) is not containing this one.
Anybody to say more?
Image is from the web.