A friend of mine in high school had his AR-15 out with him while him and his dad were on the ranch near a pond. A duck starts coming in, and his dad bets him that he can't hit it with the AR-15 (both of them have bushmasters). The kid, not to be upstaged, brought the rifle to his shoulder, took one shot, and blasted the bird "in half and then some" (his words). When his dad asked him to replicate, he refused. He knew when not to tempt lady-luck, I assume.
They were on probably 100 acres of private land.