40x46R CN Cartridge

Can someone tell me about this CN teargas cartridge?
Marked RP 711-CN by DAG. Made in 1988?
What does RP stand for and why such a long projectile.

Overall length is 181mm.

RP is part of the factory designation (have not seen them explainiing it). Projectile contained a CN (irritant) load.
Length: the more the better!

RP = Reiz Patrone ??

It could be “Reizstoffpatrone” but it is all speculation without a factory document stating on this.