Slipslinger Grenadier (Combat)Source Weapon Master's Handbook pg. 13
You can hurl splash weapons with your sling.
Prerequisites: Slipslinger Style, Throw Anything, Weapon Focus (sling) or weapon training (thrown) class feature, warslinger racial traitARG.
Benefit: While using Slipslinger Style, as a standard action you can use a sling to hurl an alchemical splash weapon, treating it as a sling bullet for the purpose of drawing and loading it into your sling. Your sling deals its normal weapon damage, plus the loaded splash weapon’s effect or damage. This extra damage is not multiplied on a critical hit.
Special: This feat cannot be used with alchemists’ bombs.