Bama, Back in the late '70s, I got interested in shooting 38s for accuracy. In spite of the manuals of the day allowing for a little more powder, every old hand I talked to, recommended 3.2 grains of Bullseye behind a 158 grain bullet.
It shot great then and still does when I get the time to load up a few for my S&W Model 14.
It's the powder charge I use when I seat a 158 grain RNFP bullet out to 1.51" OAL in .38 Special brass to assure smooth functioning in my wife's .357 Marlin cowboy rifle loads. No doubt, owing to her skill and speed rather than my loading abilities, they've helped her win a couple of purty prestigious titles in that game.
If my records are to be believed, 2.8 grains of Bullseye with the Star 148 grain HBWC recorded, by FAR, the smallest groups I managed to log with the 52 Smith I owned 30 years ago.
Concerning the Model 52 and the 148 grain HBWC, the 1979 Speer manual (mine is tattered but still readable), on page 360, stated:
"These loads are intended for use in target autoloading pistols. Velocities were measured with a S & W Model 52. The second loads for each powder were the lightest charge giving reliable functioning and excellent accuracy. The higher charges should be considered maximum for best accuracy. These bullets must be seated flush with the case mouth to function in the Model 52." It continues by listing:
231-max of 3.3 for a velocity of 805 with a "second" or beginning load of 3.0 chronoing at 747.
HP38-max of 3.2 for 804 fps, with the beginning load of 2.9 booking along at 756.
Bullseye- 3.0 for 790 fps, 2.7 for 729.
Red Dot- 3.0 screaming along at 826 fps, with 2.7 getting 763.
700X-2.8 for 782, 2.5 for 731.
PLEASE NOTE THIS DATA IS OLD. Powders may have changed or lawyers may just be lurking behind more trees but these numbers always worked for me.