Walther vintage sight aperture thread size ?

[Pastprime]

I bought a pre WWII sporterized German training rifle with what I believe is a Walther rear sight. I found a photo of the same style sight and it was referred to as a "round" or "sport" sight. The threaded portion of the aperture measures .253". No idea what the pitch is. Does anyone know what the correct size in mm would be. I would like to have another rear aperture made.

Any help appreciated.
Hank

[moonlightrun]

Try Earl's Repair Service he is a Walther guy

540-921-0184