Sling should use EITHER Dex or Str or berhaps both

The sling seems severely misrepresented in D@D.  The Roman era skirmishers were typically slingers, not archers.  Range is clearly defined in the PHB (it should be between shortbow and longbow, but it is what it is.)  What is not clear is whether to use Dex or Str as the ability modifier.  Sling does NOT have the Thrown property, just Ammunition, but intuitively it feels more like a thrown weapon since the motive force is the limb of the weilder, not the limbs of the bow/crossbow.  A light crossbow bolt fired by a character with a 13 Str hits as hard as one fired by a character with an 18 or an 8.  A sling bullet is going to have a lot more speed when slung by a stronger character and hence whould do more damage.

The Sling is a ranged weapon.  The ability modifier to apply when making a ranged attack with a weapon is Dexterity.