Range for Slings

Gladwell discusses the capabilities of the sling at (magnificent) length in the David and Goliath chapter of his new book. Personally, that was the only chapter I found compelling, and I've read every word he's written, so I'm predisposed to like his stuff.

 

The answer is about 100-300 feet depending on the proficiency of the user, the length of the leather thong (typically between 10 and 18 inches) wind conditions etc, and the design of the 'bullet' (rough stone vs smoothed) and so on. This is largely based on the accuracy of the user as well, anything above 80 feet requires a lot of practice and skill to get further distances.

A sling is a force multiplier, based on the strength and agility you transfer into the weapon as it spins, multiplied by the length of the cords holding the pouch where the bullet sits. The 'knack' to getting greater range comes in the trajectory the bullet is thrown.

A competent, proficient user, throwing at an elevated trajectory can reach around 350 feet on average with a sling. This is all based off an old discussion I had with a Medieval Enthusiast I met at college (Also a mathematician who liked to discuss/bore us with discussions like this. He played Dragonlance, he was a Kender named Bob.)

 

Like many ranged weapons, the strength of the sling was the mass volley. The Slinger didn't have to be that accurate, just hit a group/horde opposing them.