This game does give Courtesy Drops. Run yourself out of ammo and wait a few seconds. It will auto refill your reserve primary and Special ammo completely and even give you some heavy. But like everything else in this game the really good ideas were left behind in D1 with Ammo Synth. A consumable you could pop mid fight in case the game starvs you of said ammo. Btw: in D2, Juggler is Always active!