The area related to markings of the M91/30 rifles and its variations, like M38 and M44 carbines and others, is very voluminous, and will be difficult to completely cover in detail, however, this project will bring light to many earlier unknown aspects of various markings.

All markings on the serial (non trial) M91/30 rifles, M38 and M44 carbines (and other soviet firearms) can be divided into the following groups:

1) Factory markings, stamped during production, these were:
- main markings that were present in production drawings;
- operational markings and proof marks;
- markings about specific rifle/carbine configuration (training, sniper, etc).

2) Factory military representative acceptance markings, stamped during production, these were:
- personal marking of the chief military representative;
- personal marking of the military representative office worker;

3) Repair depot markings, stamped during firearms repair/maintenance, these were:
- repair depot ID/logo markings;
- operational markings and proof marks;
- quality control markings;
- markings related to the change of the rifle's/carbine's status (conversion to training rifle, or non serviceable condition)
 

All of the hundreds known and unknown Soviet markings and proof marks are from those three groups. Groups 1 and 2 will be covered in the section about production markings, group 3 will be covered in the section about repair markings.

The Soviet military never used any unit markings, like markings about district where firearms were used in service, what units they belonged to, etc. All markings were related to the processes of firearm production and repair. The main purpose of  the production markings and proof marks was to record all production stages and people who were responsible for them, that's why personal markings were used so widely. In case something was broken during a rifle's service life, it was possible to find out who was responsible for acceptance/quality control and where the defective part/rifle was issued. All this was made on practice - there are many documented cases of investigations into broken parts and the causes of failures.

One of the interesting things about these markings is that some were mandatory while others were factory established/specific. Mandatory markings were mentioned in the highest level documents (production drawings, technical conditions for production), non mandatory markings were established by factory directives. These lower level markings are mainly operational, in the majority of cases they were personal markings of the workers, they look like different letters and numbers. Workers marked some completed operation during production which identified the person who was responsible for them. Outside of that they did not contain any significant informational value. Often people buy M91/30's and start to look for information about the meaning of the single letters and numbers on the stock and metal parts, but there is nothing particularly special about them.

Mandatory markings are much more important as they contain information about the most important production stages.