In the 1930's the German military standardized the 7.92x57 loading as a 198 grain FMJSBT. The bullet was a lead core with a mild steel jacket with a nickel coating. Powder was square flake, non corrosive. Mausers published data showed velocities from 29 and 23.5 inch barrels. 2575 fps from the 29 in. and 2475 fps from the 23.5. American load manuals are anemic for liability reasons, the existance of the older .318 bore 8x57J rifles. I have had very good accuracy with 46 grains of IMR 4064 behind a 200 grain Sierra MK or Speer Hot-Core(for hunting),from my 98k's. MOA for the Speer's and sub-MOA with the MK's. The velocities were only averaging 2350. That is the MAX load listed in the Speer #12 manual. I recently tried Vihtavouri N150. There load data is in the European standards for the 8mm. A MAX listed charge of 49.5 grains yielded an average velocity of 2487 fps but accuracy was less than the IMR 4064. It was still acceptable at about 1.2 to 1.5 inches at 100 for hunting. But achieving another 100 fps wasn't worth the extra cost of the VV powders. I have a feeling that case life might suffer as well. Oh before I forget, I used Remington brass and Winchester LR primers. Sorry for the long winded response, just trying to help. I need to sit down.
