Zobex, that is some creepy stuff indeed.
What about the single, lone rifles found, without anything else around them, can that also be a marking?
I was brought to a site just last week, a series of cut limestone tunnels through a series of large rock formations.
It was a large camp area, anyway, at one end of the land, away from the tunnels, around 30 years ago, kids found the butt of a rifle sticks out a crack in the rock, and it took some time for them to pull the thing out, it was stuffed into a solid crack in a sort of stone roof, but below it is a soft spot, which looks like it may be back filled. Father was a religious nut so he grabbed the rifle and hid it again...