The amount of powder you dump into the case has a direct relation to the pressure in the case. The pressure in the chamber has a direct relation on the muzzle velocity. However in both instances the relationship is not linear.
.357 has twice the pressure of 38 special yet the velocity is only 50 to 70% higher.
The best way to ensure you avoid excess pressure would be to consult multiple reloading manuals and discard data that appears to be an outlier