I concur with the majority here that the 158gr bullet is the way to go in fixed sight 38 Special revolvers. I have one J frame however that is an anomaly. That is a BODYGUARD BG38 with Crimson Trace® Laser that I bought new in November 2014:
M&P(R) BODYGUARD(R) 38 Crimson Trace(R) | Smith & Wesson
For some particular reason, that gun is regulated to shoot to point of aim (using the iron sights) at 10 yds with the Hornady® Critical Defense® 110gr FTX® Standard Pressure (#90310). It is spot on at that distance. I have since regulated the laser so it sits atop the front sight blade. Thus the gun is dead on at halitosis range with either sighting system.
The only thing I did to the gun was to replace the factory grips with the Hogue® Tamer™ to get a better purchase on the firearm.
What ammunition do my fellow BG38 owners shoot in their guns?