Before the gun, there was the slingshot. In ancient Greece, rocks or "slingshot bullets" were flung at enemies. These bullets were about 43 millimeters long and weighed about 105 grams.
Archaeologists discovered some of these rocks in Athens, Greece and dated them as being from the 4th century BC.
In a cruel or perhaps just ironic twist, the bullets were inscribed with the greek word "Dexai." This means "catch!" Or "take that!" Just in case the flying rock at your head wasn't message enough.