I have this Recoil sight on my desk. I make the web small then there is my desk top. My father-in-law gave it to me. I think it is a disk. Other than that I couldn't figure it out but there is a way. I have another one in my favorites, I could E-Mail it.
In order to figure it you need the weight in grs, like a 250 gr bullet or 180 gr bullet, There is a way to change ounces to grs it is in one of my books, and you need the velocity, like 3000 fps or 2950 fps. With these you can get what you need to know.
