It appears that the Armored and the Tank Destroyer Boards were already approving the T122 variable power telescopic sight for standardization for use in their armored vehicles, now designated as the M83 at the behest of Army Ground Forces in June 1945.
You might notice that this telescope was only ever described in gun technical manuals and vehicle technical manuals shortly after the end of WWII, leading to a belief that this sight was only developed postwar. Some of the most notable tanks to use this sight were the M46, M47, and M48 Pattons. However, it has been confirmed that this sight did indeed exist for a while now, with the earliest development beginning as early as March 1944.
It is a variable telescope with a magnification range from 4x – 8x. This variation is obtained by turning a knurled head by which one can obtain any power between 4 and 8. The true field of view varies from 14°27′ at 4x to 7°36′ at 8x.
The vehicles to receive the telescope are sorted by priority, as follows:
(i) 90 mm Gun Motor Carriage M36 Series
(ii) Heavy Tank M26
(iii) Medium Tank M4 (76 mm) Series
(iv) Light Tank M24
All classes of US late war armor from tank destroyers to light tanks were in transition to equip this new variable power telescope, in addition to retaining their then-current telescopic sights as backups, mostly M71 and M76. Heavy tanks and tank destroyers would use the M83C type, medium tanks the M83D type, and light tanks the M83F type.
Also, the T26E5 and M26E1 were also being diverted from using M71C to M83C midway through their development as well. Though this change was not reported in the standardization plan, since these tanks were still prototypes.
really cool, thanks for finding this info