Sling Hit 175m (574ft) 

Slinging like the Romans. This distance(175m) is close to a stadium ("The stade consisted of 625 Roman feet (185 metres or 606.9 feet), or 125 paces, and was equal to one-eighth of a mile").
This is the distance ancient Romans trained daily according to de re militari, their targets were consisted of bundles of twigs. My target consisted of branches, twigs and a metal mesh to support an archery target face.
Ammo was river stones.