英语都会，我就不翻译了
To the left there is a Soviet memo on the subject of the experimental carbine designed by a Colonel P.I. Mayn. The memo reads:
To the chief of the Red Army GAU, General-Lieutenant-Colonel comrade Yakovlev
The faculty of aviational armament in the Zhukovskiy Military Air Academy, under the supervision of a lecturer from the department of gun and machinegun armament Colonel comrade P.I. Mayn, designed an experimental self-loading carbine. The prototype was built by Junior Military Technician comrade A.V. Ivantsov and Senior Technical Lieutenant comrade V.S. Usantsev.
The self-loading carbine uses a 7.62 model 1930 pistol cartridge [ed: 7.62x25mm Tokarev], and demonstrated satisfactory reliability, accuracy, and precision.
The carbine is simple, easy to operate, does not require a special tool to assemble, disassemble, or manufacture, and can easily be manufactured on ordinary equipment with up to a medium degree of wear.
The carbine has definite advantages in its tactical-technical capabilities compared to the self-loading model 1940 rifle or model 1891/30 rifle for use by artillery, engineering, communications, airborne, other specialized units, and infantry commanders.
I give you the sample of the carbine and ask you to ask the State Committee of Defense about its adoption into service by the Red Army.
The author of the design, Colonel Mayn, and Chair of the department, Brigade Engineer M.V. Gurevich, are sent for a report.
Attachment: description of the self-loading carbine on 5 pages.
Military Commissar of the Academy, Vakin.
Unfortunately, we only have a single additional page on the weapon, although it does include photos of three different examples of the carbine: