I have a photo of Frank Sutton's 1231 K50 but don't know the size for sure. Judging by the 2 x 2 it is around 37mm. But yeah, probably 39mm.
I think that it would probably measure around 34-35mm. That is what the ones that I have had the chance to measure came up.
I have a photo of Frank Sutton's 1231 K50 but don't know the size for sure. Judging by the 2 x 2 it is around 37mm. But yeah, probably 39mm.