Hodgdon 2023 Annual Reloading Manual lists the following 38spl loads for a 146 grain Speer JHP out of a 7.7\” barrel with a WIN SP primer and a COL of 1.37 – (That seems awful short to me. I would load it longer):
HS-6
Start: 5.6 grains = 808 fps @ 11,700 CUP
Max: 6.3 grains = 969 fps @ 16,100 CUP
700X
Start: 3.2 grains =724 fps @ 13,800 PSI
Max : 3.6 grains = 815 fps @ 16,000 PSI
CFE Pistol
Start: 4.7 grains = 845 fps @ 13,000 PSI
Max: 5.1 grains = 964 fps @ 15,700 PSI
Good luck!