I'm running something similar but without Bestial Frenzy and Gods amongst Men and have Branded Burst instead of Acute Tracking and do nowhere near 150k (nor do you).

During this video, after Mark Of Impurity, more than 1000 Rage. My Gunslinger crit will varies from 100,000 - 160,000. And ofcourse if you hit the creeps that are close to each other, damage will be double to atleast two of them.

I honestly don't care if you managed to get that much ONCE under some really rare conditions. When you say you do X damage you take an average. Your average is WAAAAY lower than what you claim, especially if we count the non-crits.

As for GB: if you'd use order through chaos you'd do more damage. The AOE isn't even working. I've tried it now, but didn't notice any damage on nearby opponents. I've tried it in town as well on the barrels. 2 barrels down: one front and the one behind, but the 3 barrels next to them are still standing and it's supposed to deal AOE in a 2 m radius. Must be some tough barrels!

Btw. how does Gods amongst Men work out for you? I find it absurd to waste 3 points to get a lousy +50% additive material damage and not being able to do anything else. For 3 points you can take 3 x +15% material damage nodes and be at +45% and still be able to do other kind of damage.