This has been the preferred handgun of my family. My grandfather used his as a merchant policeman. Unfortunately, it was lost long ago in a boating accident.
My father always said that the .38 special round had extra charge so that the bullet impact would knock down the target.
My grandfather carried one in his capacity as an armed Postal Agent back in the Depression when big dollar stock certificates and bearer bonds, etc. were hand delivered by the Post Office.
Alas, it too is lost to the mists of history.