The rearsight adjusting wheel is a solid one piece part on the breakdown. The wheel which is in two parts with the central spring loaded plunger came in with the postwar Cadet Major, and Airsporter Mk1's. You do see a lot of earlier BSA's which have had this sight added at some point, but it is not right for pre-war guns.


See here for some good images

https://forum.vintageairgunsgallery....ern-1933-1939/

The adjusting wheel showing on rifle s/n B2528 is the wrong wheel (from a later Cadet Major or Airsporter Mk1 ) as it has the hole in the centre for the spring loaded plunger.


Lakey