The I-frame was originally produced in .32 S&W Long. The 5-shot .38 came later.
Back around 1953, I spoke to a county sheriff in Mississippi about the Terrier he was carrying in an OB holster.
The Chief's Special in .38 Special was introduced in 1952.
In 1950, Col. Rex Applegate was involved in a deadly force incident in Mexico City. He was extremely dissatisfied with the performance of his S&W Safety Hammerless revolver chambered in .38 S&W.
That and his discussions with W. H. B. Smith led to the development of the S&W Centennial in 1952. The Chief's Special was already in production.
It became extremely popular, but the geometry of the mechanism results in an inherently low mechanical advantage for the trigger, and the trigger pull is far less than optimal. And while six shots might seem to provide only a 20% advantage over five, a little statistical work belies that conclusion, Had I carried an undercover revolver in the 1950s, it would have been a Colt with a hammer shroud.
Today, the Kimber K6 provides six shots with a great trigger and a concealed hammer in a small size.
I have my grandfather's I-Frame .32 Long Regulation Police revolver. He obtained it from a police officer who had divested it immediately after an incident in which six shots into the upper chest of an attacker failed to effect a rapid stop,
