Howdy
As has been stated, when S&W developed the high velocity 38 Special load, they chambered it in a large N frame revolver. This size was chosen because the cylinder was large and would have more steel between the chambers than the cylinder of a K frame revolver. S&W did not feel the steel available at the time was strong enough for the pressure developed by the the high velocity 38 Special rounds in a K frame cylinder.
The N frame had been developed for the 44 Hand Ejector, 1st Model (the Triple Lock) in 1907. So the logical choice to name the new revolvers was 38, for 38 caliber, and 44, for the N frame usually associated with 44 caliber revolvers.
There were two versions of the 38/44 revolvers. The 38/44 Heavy Duty model with fixed sights was introduced in 1930. This 38/44 Heavy Duty shipped in 1931.
The 38/44 Outdoorsman with adjustable sights was introduced in 1931. This 38/44 Outdoorsman shipped in 1933.
This photo of a 38/44 Heavy Duty cylinder illustrates how much steel surrounded each chamber.
In 1935 Smith and Wesson, aware that a shooter might chamber one of the high velocity rounds in a conventional 38 Special revolver, lengthened the case by about 1/8", creating the 357 Magnum cartridge. A new revolver, simply called The 357 Magnum was created at that time for the new 357 Magnum round. This led to the Registered Magnums, which had a production number stamped on the frame and they were registered at the factory to the owners. In 1957, when S&W changed over to a model number system, The 357 Magnum revolver became the Model 27.