In 1935, J. Edgar Hoover, Director of the FBI was presented with the first production .357 Magnum - Factory Registered.*
It was a 3.5 inch N-Frame. This revolver evolved into the Model 27, The .357 Magnum.
More recently, within the last 30 years or so, it was a Model 13, with a 3 inch barrel.
*Ref. The Standard Catalog of Smith & Wesson, Supica and Nahas