In Rav´s opinion, if it's not made heffker is going to be liable for kelim so how is he going to make the guy who threw the Keli and damaged liable (throwing somthing at a stone surely is considered as hefker)
David sadovitch, Mexico City Mexico
1) The Rambam (Hilchos Chovel u'Mazik 6:10) writes that if someone threw a stone and it caused damage, this is equivalent to damaging directly with one's hands and is in the category of "Adam ha'Mazik."
2) Throwing a stone at a person or at property is the same as hitting him directly, because it comes from the "Ko'ach," the strength, of the thrower.
3) When a person throws a stone, it is not the stone that damages; it is the person who throws it. "Adam" -- the Man who damages -- is a very different category of damages than the Bor (pit) mentioned on 28a-28b.
Dovid Bloom