The force of your sling attacks can pierce armor.
Prerequisite: Str 13, Weapon Focus (sling or halfling sling-staff).
Benefit: When making a sling attack against a target within its first range increment, the target’s armor or natural armor bonus to AC is reduced by half.
*This feat benefits users of the sling or halfling staff-sling, and is the original concept of Weirdo and Xunal on the Homebrew thread of the Paizo RPG website. (Weirdo; Penetrating Sling feat)