i saw some guys shooting arrows with table tennis balls with a few drilled holes just behind the tip of the arrow. this idea wouldn't work for slingshots because the ball is turning during the flight. <br><br>does anyone know how to make simple whistling balls? i know there do exist dog fetching whistle balls, but they are too big for normal slingshots and not easy to make, i think. dunno how they look like on the inner side.