The nomenclature is a bit confusing, one might argue snub Magnums are more of a CCW than a "Combat revolver" .

Prior to the introduction of the 4" Combat Masterpiece the only options for a 4" S&W duty revolver in .38 caliber were
the K frame M&P, N frame 38/44 HD or N frame 357 Magnum.

The name Combat first appears on the "Combat Masterpiece" (pre Model 15) and its .22 sibling (Pre Model 18) in 1949 and became a regular catalog item in 1950 ,
The name "Combat" was applied to distinguish the 4" versions from their 6" "Masterpiece" counterparts before the advent of model marking.

In 1954 S&W introduced the Highway Patrolman (pre 28) as a cheaper alternative duty weapon with target sites in .357 caliber ,

The 4" K target frame .357 "Combat Magnum" became available in 1956 as a lighter alternative to the bigger N frame 357's
and in SS in 1970 as the Model 66.