sling vs bow

[M. Demetrius]

Could the heat of a sling bullet be due to the lead bullet being used straight from the mold

I thought about that, but then I thought, "How would a guy pick the thing up, and since slingers were mobile, how would you keep coming back to the mold, and wouldn't the hot metal damage the sling (which was basically made out of dry grass or equal)?" So if the bullet actually picked up heat, and that's not just an ancient urban legend, it would have to be from air friction.