The CENTRAL was first patented on 31/5/34 as application 17801/34 and after two years of litigation due to patent conflict, was formerly accepted 6/6/35 and cleared for production 22/10/36 with cognate 20278/34.
The first sight with rearward facing scale plates was available for sale prior to patent acceptance and was used to win the NSW Queens in 1935, Victorian Queens and Queensland Queens in 1936.
The second model, designed to be used with an adaptor side mount, was slightly shorter. by 1940 the third model, The Bisley was in production, with modified windarm and multi position base mount, allowing it to be used on both types of Central mount plates available.
This was the sight that was impressed in 1940/41 for military use.
The Central No.4 that we are familiar with was released in 1942, but was not in production until post war, about 1948/50.
Minor modifications to this model were made up until patent Expiry in 1970, after this time various clones were made.
A more rugged version of the Central was made in Australiaand first manufactured as the MacRorie, than later as the T MAC.
All versions are still in use today, servicing of worn sights is still available in Australia thru Mal MacKenzie at SIA.