Smith & Wesson K-22 Model 18
.22 LR K-Frame revolver
This is a 64 year old revolver. There is wear on the finish, some of which may be surface rust; or not, I'm not really sure. Nobody is going to mistake this for a new gun.
The serial number on the inside of the grips matches the serial number on the frame.
There is no model number stamped on the frame. 1957 was when Smith & Wesson introduced model numbers, and began stamping model numbers on the frame. So this is either the last of the K-22s or the first of the Model 18s.
In 1949, a 4-inch barrel version, the K-22 Combat Masterpiece was introduced. Later it was to be called the Model 18. It was a great little trail gun, but sales paled compared to the 6-inch barrel version, and it was discontinued in 1985.
Throughout the 1950s, several small changes were made to all Smith & Wesson revolvers. The four-screw sideplate became a three-screw sideplate with the elimination of the top screw in September 1955. Model numbers — which were introduced in 1957 — began being stamped (17) and extractor rods started getting left-handed threads in December 1959 (17-1). The cylinder stop was also redesigned, eliminating the screw on the front of the trigger guard at the end of 1961 (17-2).
-- A Look Back at the Smith & Wesson K-22 • American Rifleman • 11/13/2012
This is the portion of the frame, under the rear of the barrel, where the model number is currently stamped on S&W revolvers.