Protip: Aiming at maxim gunners is not always the most optimal way to use rifle grenades. There are 5 other crew members that can't swiftly dodge the grenade. Some of them are bound to bunch up at some cover. Aim it at them instead and you will score a lot more kills.
I will give this a try good idea.
But killing the gunner also stops the burst from the weapon and that gives some other advantages.