Quote Originally Posted by Darth Stalin View Post
Nope; think about the stones/lead balls as ancient "armour-piercing, high-speed projectiles" - these being shot fro modern tank guns also have high speed and flat trajectory, while being able to fly on quite long distances (2-3 km) - due to high speed and horizontal acceleration.
Well... a stone thrown from a sling would never achieve the speed of a gun-powdered bullet/cannon ball, especially, the modern ones...

As to the sling efficiency against armour: i think, there was a reason by middle ages no european/muslim army unit was specializing in throwing stones around anymore ;)