Beating on an Old Old thread here. A handloader using a more modern solid frame revolver, not a top break, can duplicate .38 Special ballistics in the .38 S&W safely. Factory .38 S&W loads (except for BB) are anemic because of the many thousands of weak old break-top revolvers from the black powder era still around. I think BB warns against using their heavy loadings in top break revolvers.

There is absolutely no doubt that a heavily loaded .38 S&W is ballistically superior to any .380. Everyone seems to think that 0.360"-0.361" bullets are necessary when reloading for the .38 S&W, but that is absolutely false. .357-.358 lead bullets will work fine, I have fired thousands of them. In fact, the SAAMI minimum bullet diameter specification for the .38 S&W is 0.355"