The Serangan looks pretty similar to the M1 Dispersion, except it doesn't have the dispersion option. What advantage is it supposed to have?
It's supposed to be the Exor but better, essentially. I read Gavrilium as an extremely energy-dense solid that can be used as fuel or explode impressively under the right conditions. Using it as an explosive lets us get more boom by weight and makes huge grenades feasible, but my thinking is that it doesn't make sense to make grenades larger past a certain point, because the bigger they get the harder it is to throw them accurately at a distance that doesn't put the person doing the throwing at risk of being too close to the thing when it goes off. Some grenades are designed with cover in mind and don't really care about this, but given the era it seems like grenades will be mainly used for urban warfare and assaulting trenches and other emplacements. In urban fighting it's very close quarters so you don't need huge yields anyway, so I figured it would be more valuable to the average soldier if they were able to carry more of them. Trenches and things like machinegun nests are both difficult to approach and designed with localizing the damage caused by large explosions as much as possible in mind, so I figured that saving weight and being able to throw the thing accurately from farther away would be more valuable.
I'd support something like the M1 if it were a mortar shell or something like that, but as a hand-held and hand-thrown weapon I feel like it's too situational, and I'm also concerned about the expense and complexity that selective submunition dispersal would add to the design.