The Belgian military issued a 9mm Nagant revolver called the model 1878 and then an improved one called the model 1878-86. The cartridge for the Belgian revolver is often called 9.4 mm, which reminds me of the Dutch 9.4 service revolver but the two cartridges are not interchangeable. The Dutch revolver has a larger bore diameter. The Belgian Nagant bore size is smaller. Dutch 9.4 military cartridges will not chamber in the Belgian M.1878-86.
Does anyone have case and bullet data for the Belgian service revolver cartridge? Size, weight and length of the bullet would be interesting. There is rather limited information about this round on-line.