People sleep on how deadly a sling can be:

On a fortified hill in Scotland some 1,900 years ago, a Roman army attacked local warriors by hurling lead bullets from slings that had nearly the stopping power of a modern .44 magnum handgun, according to recent experiments.

www.nationalgeographic.com/history/article/ancient-slingshot-lethal-44-magnum-scotland

Even with simple ammunition, the sling was surprisingly effective. Slingers could achieve faster “muzzle” velocities than archers, and their projectiles suffered less air resistance during flight than arrows, conserving more kinetic energy until impact. An experienced slinger could throw projectiles at speeds over 90m/s, while the longbow could fire arrows upwards of 60m/s (Gabriel, 1991; Richardson, 1998a). When projectile masses were equal, the 50% speed advantage of the sling equates to a 125% increase in kinetic energy (because the velocity value is squared). Despite this, the penetration of an arrow was still greater because the tip is roughly 24 times smaller than the side of a typical, spherical sling projectile. The impact force of a sling projectile was applied to a larger area during contact, making it unlikely to penetrate flesh, though the collision could cause internal bleeding and even crush bones (Ferrill, 1985; Grunfeld, 1996). Historical demonstrations of this power have crept into literature, providing unique, first-hand accounts of professional slingers in action. For example, during the Spanish conquest of the Incan empire in the 15th century, an observer recorded that Andean slingers could shatter Spanish swords or kill a horse in a single hit (Kormann, 1973; Wise, 1980). Vegetius, a Roman writer in the late 4th century, observed in his famous Epitoma Rei Militaris:

Soldiers, despite their defensive armor, are often more aggravated by the round stones from the sling than by all the arrows of the enemy. Stones kill without mangling the body, and the contusion is mortal without loss of blood.

https://www.chrisharrison.net/index.php/Research/Sling