Don't blame the manual, blame the gift giver, who obviously didn't put enough thought into making sure what it offered is what you needed.
No loading manual is going to be, or can be, all things to all people and cover every possible cartridge and load combination.
The fact that the 7.5x54 is still used by a major army isn't really germane. It's not really used that much HERE, in the United States.
Yes, there are a few freaks, er... die hards...
who load for it, but I'd suspect that there really aren't that many of you.
It can take well over a year for a company to do the in-depth testing required to develop the loading data needed for a cartridge. It is not a simple process by any means, so in a lot of ways, especially with these older military surplus cartridges, it becomes a cost benefit exercise.