Gary,
46 grains is what I used in my Krag rifles and carbines. Only use 48 in stronger rifles...but also doubt that 48 would harm any Krag-Jorgensen in decent shape. Hodgdon lists 46 grains of at 38,700 CUP with the 180 Speer Grand Slam. The basic rule of single-based powders is that pressure increase at twice the rate of the charge, so 48 grains would be around 42,000 CUP--slightly higher than the pressure of the .30-30.
