For further instruction on how these grenade launchers work load up Warhammer:Space Marine on your favorite gaming platform and make it to near the end of the game, where you unlock the vengence launcher. So over powered because the game characterized realism with cover systems. There-by making a gun with explode on command ammo way to over powered so had to be limited to lower ammo so as to no unbalence the game.
This gun application in warfare is quite potent, a fact video games have known for quite some time. And thankfully, unless your on the recieving end, in real life the ammo count is only limited to how much lqmt u can afford ;)