And then you start playing around with the skill-tree builder, and realize that with 5/5 in Inconceivable and 5 Shots or 6, a Gunzerker can potentially milk two to eight hundred shots out of every hundred ammo, before taking into account Gunzerk's built-in ammo regen. Assuming the progression holds steady, with a class mod boosting you to 9/5 in one (or, cog forbid, BOTH) of those skills, as little as 5% of your shots will consume ammo when in critical condition, and far more will give it back (9/5 5 Shots by itself lets you fire each bullet nearly ten times over while active). Similarly, 5/5 Last Longer and Yippee Ki Yay will drastically extend your Gunzerk time -- in the release trailer, once Salvador enters Gunzerk in the fight versus the Bolivian Army, he's not going to leave it until either he or they are all dead.