Camba: with the 158 gn swc or rn slugs you can use a couple of charges to get you to the 826-850'/sec standard velocity for the 38 Spl with that/those slug(s): 6.0 of SR 4756 is highly recommended as a accuracy load; 4.5 of Unique with that weight bullet gets you right to 850'/sec, as does 9.5 of 2400.
In addition, I have always liked Winchester powders and like how WW231 performs. 4.3 gns of WW231 is the factory duplication load, at 865'/sec with either 158 gn slug. But, I hafta admit that I am overly fond of the 200 gn cast SWC from either Mt. Baldy Bullets or Colorado Cast Bullets over the WW231 factory charge of 3.8 gns. Very accurate, a hoot to shoot, and standard pressure loadings.
Gotta tellya that from my snubbies, those 200 grainers move slowly enough to see the bullet travelling downrange when the ground is covered by snow or even on a bright day, and you should hear them smack a 12" diameter gong, or metal plate at that distance. Fun part is being able to adjust your fire for target aquisition. Good luck and HTH. Mikey.