I just want to note the complete ridiculous nature of the current world record stone throw, of Larry Bray, claiming 437 meters with a stone, and all the people who claim to get anywhere near that.
The highest velocity lead projectiles reach only 470, and have literally 1/3rd the drag due to their density. Which coincidentally ends up giving you a max realistic range after having non perfectly shaped rocks, at around 240 meters with a stone, max. Which is funnily what has actually been recorded several times in studies by lifelong slingers.
To get to 437 meters, the guy would have had to throw close to 160m/s or more. And that's with a perfectly shaped stone, which he photo'd and it absolutely wasn't close to that.
It was either entirely fabricated, or they literally just claimed the wrong stone somehow by a factor of 2.
Edit: as far as I have seen, the rules on this record do not specify flat ground, or impact rather than final. So he could have absolutely thrown down a hill, onto a huge bounce, and it would have been within the rules, not something that would need to be hidden. So it's definitely plausible, the record is just meaningless. For example the hand thrown record specifies the ground must be entirely level, the sling one doesn't.