|Complete The Once and Future Slab||30||Bounty Board (The Highlands - Overlook)||7890 XP, Sniper Rifle|
This side mission has the simple task of just killing 100 total bandits anywhere in the game's world. However, there's a slight problem with just killing 100 bandits, which comes in the form of the four optional objectives, should you want to complete them. Each one will task you with killing 25 bandits each with one of the four elements listed under your main objective (fire, corrosive, shock and explosive). If you haven't figured it out by now, you see that all of those add up to the total of the 100 needed kills.
That means you're going to need at least one of each of the above elements to get all of the optional objectives. The best thing to do is to concentrate on a single element and carefully keep track of the kills without going too fast. Rats, Bikers and Sand Pirates are all counted as bandits and Suicide Psychos that kill themselves are non-elemental, despite being blown up by grenades. You also want to avoid vehicles, as blowing them up will count as more than one kill. As long as you kill a bandit with the appropriate weapon, it will count towards the optional objectives. Large masses of bandits include Southpaw Steam & Power, Lynchwood, and the path leading up to Captain Flynt towards the beginning of the game.