NUKZ minigun shooting mini-mininukes/mininukz. They are basically heavily modified MIRV child-projectiles, so your game won't be so laggy as it is when shooting regular mininukes-minigun, and you will not be blind after firing 3 projectiles in a row, or even entire magazine.
You can buy Nukz launcher and mininukz in Diamont city from Arturo, or steal them from DC chapel (yes steal, i don't know how to mark container as common yet).

Melee sounds weird.