I remember as a boy in the early sixties in Canada there was a TV show about some medieval type character who used a sling. It was I think originally made in French but I watched in English translation. I can't remember what it was called but it had a very rousing theme song which I can still conjurer up in my mind.

In any case all the boys around where I lived made slings and copied the hero of the show. With an endless summer and an endless supply of rocks it was surprising how good you could get with it. Also surprising I don't remember anyone getting hurt!