“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.
I didn’t know this round has such a large kill radius. That explains why the rounds can kill even with the dispersal pattern that the videos typically show.