Borderlands 2: Badass token challenges: Longshot headshot

Get critical kills with sniper rifles. Easy to achieve while getting other sniper challenges inside Pyro Pete’s bar. You can also head to Caustic caverns with a low level sniper to hit crit points on crystalisks (or against any big enemy types with ray crit points) to get critical kills with sniper rifles. On pyro Pete’s bar: Accept the bar room blitz missions. The third level of the mission is repeatable indefinitely. Equip your sniper rifle of choice and head into the bar. If you need ammo, go back upstairs to the vending machine. Rinse and repeat.