groovy, groovy, groovy, approved
+1 to the above.this is nice. really really nice.
this guy has a very strong character.
but... this model is so close to very high standard, and i think it's really worth it to polish it up on its flaws. (it has some)
i highly recommend you to remake the attack anims. right now you have too linear movements, which look weak and slow. it should be fierce (according even to your concept). changing positions quickly, alternating with near still positions (especially the aiming moment. there should be a pause there). the shooting impact provokes movements that don't match the ones you made... maybe if you include the backswing from the impact in the attack anim it gets better.
the whirling gun trick right before attacking would be awesome. while a bit difficult to make.
edit: and moving the gun like that in stand ready isn't very nice. remember he's engaging combat at stand ready. he has a target and isn't idle, so he should be aiming at it already. (maybe insolently swinging each pistol in an alternated fashion to show he doesn't give a shit )
those are my tips. please don't give up on this until it is flawless