Loading a sling is a free action requiring the use of both hands. Ardents, artificers, assassins, avengers, bards, battleminds, bladesingers, clerics, druids, fighters, invokers, paladins, psions, rangers, runepriests, seekers, sorcerers, swordmages, vampires, wardens, warlocks, and warlords are proficient with all simple ranged weapons, including the sling. Rogues receive proficiency with the sling directly. Other classes do not have proficiency with the sling as a class trait, but any character can become proficient by taking a Weapon Proficiency feat.