Yeah, an early research project would be OK. That system in in the wiki is actually quite deadly because it uses proximity fused mini-grenades, so you shoot over enemy cover and the grenade detonates above or behind the target. It basically negates anything but a pillbox or covered foxhole as cover. Even buildings aren't safe because it can be set to fire through any window or opening and blowup inside. But you are right about the small size, it wouldn't destroy much cover. However, it would be a great stun gas, mine, or poison gas delivery system and it could still destroy cover fairly quickly because it can fire MANY explosive rounds quickly and that adds up. The rate of fire is important. I'm guessing, but I imagine a direct hit from a 25 mm explosive round would probably blow a two or three foot hole in a brick wall. I imagine some alien upgrades would also up the explosive power of the weapon eventually.