Sling Flail

Combat

You can use your loaded sling to effectively strike at nearby foes.

Prerequisite: Weapon Focus (sling), base attack bonus +1.

Benefit: You can make melee attacks using your loaded sling, using that weapon’s normal statistics but treating it as a flail. Using a sling in this way does not expend mundane ammunition, but magical or masterwork ammunition loses its special properties after a single hit.

Special: Any feats you have that apply when you use a flail also apply when you use a loaded sling as a melee weapon.

Source: Ultimate Combat