Didn’t those nitwits realize there was a helicopter in the area? Unless that action was photographed from a couple of miles away...looks like they were right on top of the bad guys, though!
They could have been peeking over a hill. The camera is in the pod on top. There was quite a delay from shot to impact. Maybe 2 seconds. At 2400fps thats 5000 feet.
I don’t think you realize how far away these predators and Apaches are. You would see a blip in the sky, they see the mote in your eye.
“The M789 AP/DP round is typically used in the M230. Each round contains 21.5 g (0.76 oz) of explosive charge sealed in a shaped-charge liner. The liner collapses into an armor-piercing jet of metal that is capable of penetrating more than 2 inches of RHA. Additionally, the shell is also designed to fragment upon impact. The lethal radius against unprotected, standing targets is about 10 ft (3.0 m) under optimum conditions. The M789 requires about 2 seconds to travel 1,000 m (3,300 ft). However, as the shell slows down, it takes over 12 seconds to cover 3,000 m (9,800 ft).
So it's probably still good out to at least 3 or 4 klicks, and 3k downwind will not be heard over truck and other sounds.