Odd 41mm Signal cartridge or grenade?

[ron3350]

I have no real ID on this item. Bought as a Polish rifle signal flare but I can find no info on the forums to confirm this identification.
It is made of cardboard with a hardened finish and very light (empty). I doubt that the 3 rifling projections would stand up to firing from a rifled grenade projector as made of cardboard? The base has green paint and two raised ID marks to signify green flare or maybe double green stars? I am guessing here.

Length is 61mm. Diameter is 41-41.5mm.
Centre hole is possibly for ignition from a blank?
Maybe the 3 fins are for air spin/stabilising? Similar to a cheap version of the Russian VGD signal. Lots of guesses here.
Any information about ID, how used, country and model will be gratefully received. Ron.

 

[sgdbdr]

Looks like the russian green signal VSG40 (BCГ-40)

 

[MINENAZ16]

Hello,
I don't know if informations are correct but this link could help : https://www.inert-ordnance.com/index.php/2020/04/19/rare-russian-deriabin-signal-rifle-grenade-wwii/

 

[ron3350]

I thank you both. I knew nothing about this item. I checked the marks and blemishes and think I have the exact item shown in the link.
It came from a collection that was sold recently. The nose looks a bit short in length looking at the photos. Ron.