"To the Chief of the 3rd Department of the BTU
Moscow, Red Square, NKO house #2
RE: trials of the tank sight
Factory #237, on its own initiative, designed a simplified sight for the 20 mm TNSh gun and produced experimental prototypes. The difference in the proposed sight compared to the stock one is as follows:
- The crosshair mechanism is simplified. There is no longer a horizontal adjustment mechanism. The horizontal correction grid is painted on.
- The scale and grid are no longer illuminated.
- A brake was added to the distance setting wheel.
The modernization reduces the number of parts by 40 (out of a total of 120), while the main optical and mechanical components, as well as the characteristics of the sight, remain unchanged. The sight becomes much simpler to produce.
Production of these sights will therefore increase and will be able to satisfy the demand of tank factories, which is not currently being fully met.
I ask you to issue 300 rounds for the 20 mm TNSh cannon and 120 rounds for the 7.62 mm DT machinegun to perform trials.
The trials program has been approved by the military representative, Military Engineer 3rd Class comrade Ivanov (Kazan proving grounds). Trials will be performed by the 23rd Reserve Tank Regiment in Kazan, who I ask you to send the necessary orders for the issuing of ammunition to.
I ask you to not delay your answer.
Chief of the 3rd Department of the GAU USV, Military Engineer 2nd Class, Vaisleder
Chief of the 1st Section of the 3rd Department, Military Engineer 2nd Class, Korabut
January 26th, 1942"