The Stone Arrow can be equipped to the Bow, Crossbow and Compound Bow for hunting. An unbroken Stone Arrow can be picked up by walking on it after being used. This, in combination with the low Engram cost and ability to craft them at any time out of common materials, makes any weapon that can use Stone Arrows as ammo highly resource-efficient. Use them with a Bow if you want a fast firing weapon.
There is a good chance to obtain Stone Arrows from item caches of dead carnivores. It is one of the best ways to collect Arrows directly without grinding for resources. For this reason, caves can be used as sources of Stone Arrows.