I wouldnt be surprised. Im a siren with an alkaline the bee and a non-elemental sandhawk. I constantly put out 900k crit hits on pete lol. The sandhawk is a no joke weapon if you can land the majority of the horizontal burst in the enemy crit zone.
I had 999 Critical Ascension stacks. I achieved this by having a gunzerker with team ammo on and I blasted away at the dummy in sanctuary 1000 times with my Muckamuck. First shot of the mag and deception did the rest of the damage. I even forgot to put on "The Bee".