Since we do not yet have a detailed photo of the shell to be able to write which manufacturer produced the mechanical components, we will not move further for now. But what can we say
Instead, we only have one certainty that the laboratory was carried out by OPZ.
When we go by the name of the laboratory plant listed on the drawings of the regulation (see link above) we come across the phenomenon: OPZ (Ochtinsky Powder Plant)
As a Central European, I do not normally have knowledge of the history, capacities, locations or details of the explosives industry in Russia. Even less its beginnings until 1896 when its industrial production was started in Russia.
After searching for anything that enlightened me about history, I found a significant number of monographs ... Any effort in the age of the Internet is nothing compared to going to the library
In relation to ammunition and especially dating ammunition, the turning point was 1902 when this originally one plant was divided into 3 (2?) separate entities, the first was the Powder Plant, the second was the Explosive Plant and the third was the Capsule Plant (i.e. initiators). As you can probably guess correctly, during those more than 200 years, the plant had different names.
I'm going back to ammunition ... in the drawings of the above-quoted regulation, i.e. in his manuscript (dated 1917), the state (the documents from which the author drew) is captured after 1902 when it was divided into three separate plants. And therefore it has a logical template, i.e. OZBB (Ochtinsk explosives plant) , i.e. already an explosives production plant. This is the first indication of how to date the bullet (rough range of years for now 1902 to 1918)
What can be studied on this topic:
Today the factory archive fund is located in the archive in St. Petersburg.
The fund is fully inventoried and has 7 inventories. The total contains over >1600 documents, including ammunition drawings.
Some drawings were published in preview quality on various sites. I will give an example of one drawing: 6 inch mortar (6 inch mortar with a redesign by inserting a steel barrel into the originally copper mortar.. is listed in the book's inventory)

Interesting fact: In the archive there is a drawing of the M.15 head fuze. Originally a design by Škoda Works, but when I compare it with the original it is different. It is a version that I have not known before. The text states that when unscrewing from a 6 inch shell the M.15 fuze exploded. I do not yet know who designed it, when and why.
