Vintage Nydar blued shotgun sight c.1947. Came with original lens protector, mount, carry case, and adjustment/instructions manual.
These sights are light activated, you get a large outer ring and inner dot that is projected onto the front reflective glass simply by being outside in the existing ambient light. Even on a heavy overcast day, this sight works perfectly!! This is the Model 47 and it is stamped "patent applied for". It was made by the Swain Nelson Company of Glenview, Illinois.
The basis for this sight was taken directly from World War ll. Allied aircraft had similar sights, but using the exact same principal, and shot down many axis war planes using their modified Nydar Sights. The inner dot represents 12" inches at 50 yards, while the outer ring is positioned so that the ring itself is always 24" inches from the inner dot. This makes the Nydar Gun Sight the PERFECT "scatter gun" hunting sight. In fact, as the original brochure explains, all pellets fired at a range of 25 yards was within the outer ring of the Nydar Gun Sight.
The offset sight was just me with the camera, I could not see the rings through the camera lens so I just kept on clicking untill I got a sight picture.
There are adjustments for windage and elevation, the sight is mounted on a base plate and that is able to be manipulated for front to rear and side to side movement, once it is set you lock it down.After that you can remove the sight lens - it is zero'd.
It has to be the Daddy of the red-dot sight, the only difference I can think of is that it does not work in the dark.
If you illuminated the piece (provide light) it would work.