One of the easiest ways to find those, is to use the external camera and zoom out beyond the "horizon", or rendering range of the game's "Window" on the world, if you will. One of the first things the game quits drawing is "land". Well, shrubberies actually, then Land... But "It must be one that looks nice, and is not too expensive!"...
Needless to say, this lack of shrubberies - and Land - is what exposes those gun positions, rendering them vulnerable to all manner of destruction...
Fly! Fly back home wanderer, to where your Land is once again visible!...
