Well, that worked, took about 20 minutes, I found the 900+ number of 'finds' for the word 'sight' included multiples in single patents, so the number of patents was much less, 15 to 25 a year. I guess I'll need to find another excuse to not watch the Packers Sunday.

Here's the patent for that sight, filed for in 1952, so very close to the time of the rifle that is shown with one in the first post - .uspto.gov/Pdf/2770041

Added- that type of 'aperture' is not something new, here are a couple that are quite similar -
uspto.gov/Pdf/0845491
uspto.gov/Pdf/0810761 I have an example of this sight, never was used. Mine has the 'aperture' as shown in Fig 4.

Last edited by GeneB; 10/27/23. Reason: added links
Gene