Are they located in a remote area or are there residences around? because I'm sure someone would have heard the shot, .50 BMG is loud af

edit: upon actually reading the article I saw this:

"residents reported hearing a "boom.""

So yeah, I guess it's possible.

Are they located in a remote area or are there residences around? because I'm sure someone would have heard the shot, .50 BMG is loud af

Also I'm not entirely convinced a single round, at 600+ yards would have had the energy to bust an entire slab of those, they are chunky

What makes you say the shot would have been taken from that distance though?