It is narrated from Sayyiduna Abu Tha'labah al-Khushani (may Allah be pleased with him); he said: I said: O Messenger of Allah, tell me the ruling on a found item. He (peace and blessings be upon him) said: "Whatever is found on a frequented (public) road or in an inhabited village, let it be announced for a year; if its owner is not found, then it is yours. And whatever you find in an uninhabited village or on an unfrequented road, one-fifth (khums) is due on it." I said: O Messenger of Allah, tell me the ruling about my bow. He (peace and blessings be upon him) said: "Eat whatever your bow brings back to you." I said: What if it goes out of my sight? He (peace and blessings be upon him) said: "Even if it goes out of your sight, provided you do not see in it the mark of an arrow or an arrowhead."
Hadith Referenceالمعجم الكبير للطبراني / باب اللام ألف / 18767