Russian 152mm OF-540

[MINENAZ16]

I noticed two different constructions for russian 152mm HE OF-540
With or without head screwed.
Any info ?

 

[sgdbdr]

I know these too.
I'm wondering if the two-piece one could be specific to former Yugoslavia, since the only non-nato book I have mentionning it is "MUNICIJA, DEO II, KNIGA I" (croatian language) from 1974

 

[Nabob]

IMHO it is a pre WW2 variant.
Mentioned in also in german manual D 50/8