Inland sent slides to IBM in the Fall of 43 so perhaps that explains the presence of the PI marked slide. Also, I find the rear sight very interesting. The base is forward, but the aperture is facing backwards and appears to have been customized.
Inland sent slides to IBM in the Fall of 43 so perhaps that explains the presence of the PI marked slide. Also, I find the rear sight very interesting. The base is forward, but the aperture is facing backwards and appears to have been customized.