Edited title to match the build link posted. That's a lot of ATM! How are you grouping them? Those Ghost after a pair, no? Chaining? Or firing 24, 18, 9?
Firing 2x12s in one group and then 3x9s in the other or chain fire when it gets hot. And it gets hot quick. You are paying a lot in the way of cooling, ammo count and speed to get that extra ATM3 over similar quad ATM 12 builds. Silver lining is you don't have a clan XL, so no instant side torso death.