This is KV produced copy of the Yugoslavian pre-war BRK M79 anti-tank grenade made by SRB factory.
The only difference from pre-war BRK M79 made by SRB factory is that this serbian made grenade is painted in slightly different shade of olive-drab and it doesn't have yellow marking on its body and handle.
Total length : 399mm
Diameter : 74,5mm
Weight : 1000gram
Filling : 340gram PE
Penetration (steel plate) : 280mm
Photo and info © www.krusik.rs
Additional info thanks to Goran.