http://www.youtube.com/watch?v=o4J7WzkHG_0

It's weird: [55*1.05+5+5+(27*1.5*9)]*2.25*2=1945.35

Maybe the criticals applied insane bonuses for the multiple projectiles in the blast. These are not slugs or single bullets, but a cone of fragments.

Edit:
I don't understand how Paulson's Revolver did 2294. Somethings fishy, and it's not my [censored].

Paulson's revolver works like a shotgun I recall.

Well yeah, I accounted for the multiple criticals in my equation. Also, the Paulson shoots multiple pellets and should do a max single hit damage of ((45*1.05+5+5)+(35*1.5*9))*2.25*2 or 2383.875, so it seems to have underperformed a little. Interestingly enough, when you factor in it's critical power in regular combat, without reload time, it probably has the highest damage per second of any gun after the Alien Blaster and Firelance: ((45*1.05+5+5)+(35*1.5*9*2*.18))*2.25=511.5375. That puts it above the Vengeance and the Novasurge.

Of course that's assuming the GECK ROF of 2.25 per second is correct... and there's a good chance it isn't.