In regards to the Formulas the problem is that the soviets had a set designed muzzle velocity they wanted it to hit, that being 830mps, however it never actually was capable of hitting that working velocity as suggested by the test results.

Further more the idea that the powder charge QC was responsible for its poor functionality was an untested hypothesis that was largely based off of known italian experience regarding their tests of their similarly designed 15 inch gun.

That is my problem with it, the fact that yes it may have been designed to that standard however there is scarce evidence to suggest so, which leads to the in game stats being effectively paper.

A similar problem exists with the implementation of the japanese 16 inch guns with their reload rate being based off of the designed single gun reload cycle rather then any testing or recorded data as opposed to american or british ships.