So, seeing scoring rings at 1K yds without magnification is a mental thing? Could be.
Its like a pilot spotting a camouflaged armored vehicle in a wooded area.
His memory has a file of shapes associated with numerous structures. He may spot nothing but a shadow that reminds him of some part of the vehicles outline. His mind then fills in enough detail that he'd know where other portions of the vehicle should be, so his attention is drawn to it.
The same process has been worked into methods of fooling fighter bomber pilots.
An airfield with carefully hidden aircraft may have the concrete painted in some areas in a pattern resembling a shadow cast by an aircraft to well camouflaged to be spotted easily.
In tests pilots making high speed attack runs fired on the fake shadows far more often than they fired on the real aircraft.
The visual cortex tries to connect the dots. Its why you may see a face in the clouds or other familar images.
The image enhancement software used by NASA does much the same thing with space probe images.
PS
Think of the old style printing used by Newspaper photos and comicbooks.
Seen under a magnifying glass the photos are nothing but tiny dots of varying shades. Seen normally the minds eye assembles those tiny dots into clear stark imagery.
When the tiny rods and cones of the retina pick up an image it works in much the same way, all those tiny elements become a whole.