I figured out how the bright spot works by building a Star Flash type mirror in my shop... but that doesn't mean I can explain it!

I took a Lexan mirror and drilled a 1/2" hole in the center; then I taped a piece of retro-reflective tape with a 1/4" hole in the center to the back of the mirror, ensuring the reflective part of the tape is facing forward. Then I covered the front of the mirror with a clear piece of Lexan. The mirror I came up with seems to work as well as any aim-point mirror I've used and it is less than an 1/8th of an inch thick.

The way the aim point works is that the sunlight enters through the center hole, reflects forward off of the reflective tape, then reflects rearward off of the clear outer cover, back to your eye.

I don't have the time now to build and market my version of the mirror, but I might sometime down the road. Until then, anyone on this forum should be able to make their own using the instructions above. A good place to find the mirror material is at an auto parts place in the mirror section. They sell 7"X10" sheets of mirror that can be cut with scissors or a paper cutter for about $6.00.

Hope this helps.

Semper Fi, George