http://www.thewargamersforum.com/viewto ... =23&t=5902
Having sorted that out, my project has led me down another rabbit burrow which might be of some interest to anyone planning a similar conversion...
I noticed that quite a few 1/72 and 1/76 scale models of the 6 pdr either have a very crude representation of the sighting equipment or in some cases omit it altogether (this includes the donor kit for my project). Looking at some walk-arounds of the 57mm, I saw two distinct arrangements for the scope.
This is confirmed by FM 23-75 (15 June 1944) which states:
"25. SIGHTING EQUIPMENT. a. Telescopes, M18, and M69C. ...
b. Telescope mounts, M24, M24A1, and M63, ..."
It appears the M24 or M24A1 Mount with M18 Scope is more or less the same as the Mount Mk I with Scope No22c on the 6pdr. The M63 Mount with M69C Scope has a unique appearance and is the "later" type - but I have seen examples of the earlier scope on guns with late model carriages (eg the BAIV restoration). In fact with 57mm guns it seems just about any combination of early/later features is possible, including contemporary photos where one wheel has a combat tyre and the other one has a civvy tyre!
Here are the two main types:
