Waveski
It was good that Gary corrected the nomenclature. Let me explain:

It gets its name because it is a .22 caliber revolver that was built on the .32 caliber frame (I frame) which was larger than the tiny M frame that the then-current rimfire revolvers were built on. Until 1931, S&W did not build a .22 on the K frame, so the .22/32 was called a "Heavy Frame Target" model until the introduction of the first K-22.

This same naming convention was used on other guns. For example, in 1930, the company introduced a .38 caliber revolver that was built on the .44 frame (N frame). It was called the .38/44.

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Jack
SWCA #2475, SWHF #318