The pistol (barrel/chamber/leade) will dictate the COAL.
1.150"+- is pretty standard for 124 gr. ball/FMJ, however-some guns (CZ in particular) have short(er) leades and rounds must be considerably shorter.
Load a dummy rd. @ 1.150" and (with barrel remove from pistol) drop it into the chamber. It should be just past flush, or flush with the barrel hood.
3.8 grs. with a 124 gr. Berry's should be a functional load. I run 4 gr. TG with a 124 gr. JHP and it chrono's 1050+ FPS..