Over the years people have also called these "S" frames, which is incorrect.
They are N frames, just as are all of the other large frame (the .500 excepted, of course) revolvers.
The S serial number prefix was actually first used on K frame revolvers around the end of World War II. I can't remember if before or after.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.