Howdy
I will add to the excellent information you have already gotten from cfullgraf.
With Smith and Wesson, the K frame was the medium sized frame originally developed in 1899 for the 38 Special Military and Police Hand Ejector revolvers. In the 1930s and 1940s S&W developed three complimentary target revolvers built on the same frame for 22 Long Rifle, 32 S&W Long, and 38 Special ammunition. These became known as the K-22, the K-32, and the K-38 Models. These three models all featured adjustable rear sights, a Patridge front sight, and they most commonly had six inch barrels. These were the premier target revolvers of their day.
The K-22 was the earliest of the three, first introduced in 1931 as the K-22 Outdoorsman (K-22 1st Model). This one shipped in 1935. Notice the correct service grips with silver medallions, the lack of a rib on top of the barrel, and the tiny adjusting screw on the rear sight. There is one screw on either side of the rear sight. To adjust the rear sight you loosen the screw on one side, then turn the screw on the opposite side to push the rear sight where you want it, then snug up the first screw to keep the sight in position. And you need a tiny screw driver to do this. The K-22 Outdoorsman was very popular, it was made from 1931 until 1940 and 19,500 of them were made.
In 1941 S&W introduced the K-22 Masterpiece (Prewar, K-22 2nd Model). The main difference between the K-22 Masterpiece and the K-22 Outdoorsman was the Masterpiece incorporated the micrometer click rear sight that S&W still uses today. This model also had a short throw hammer in it. The K-22 Masterpiece was only made from 1940 until 1941, and only 1067 of them were made.
In 1946 S&W reintroduced the K-22 (Postwar, 3rd Model K-22). This one shipped in 1950. This one has a narrow serrated rib on the top of the barrel and the barrel has a slight taper. Later ones had a full width rib and the barrel had no taper. Like the 2nd Model it also has the modern micrometer click rear sight. The hammer is a wide target hammer, and although it is difficult to see in this photo, this model has an adjustable trigger stop. The 3rd Model had the modern internal hammer block. This one wears Magna grips. Smith and Wesson collectors will tell you that this model is the only one that can be properly called the 'Pre-Model 17'.
In 1957 Smith and Wesson changed over to a model number system. The K-22 then became the Model 17. I bought this Model 17-3 brand new in 1975. By this time, the old five screw frames had been discontinued, replaced by the three screw frames. Notice the lack of a sideplate screw up near the hammer. This Model 17 has the wide serrated barrel rib and the barrel is straight with no taper. The front sight is forged as part of the barrel, rather than being a separate sight pinned to the barrel.
This is a Model 617-6. It was made in 2003. Like most S&W model numbers that begin with 6 it is made of Stainless Steel. It is a ten shot revolver. I actually have no objection to the lock, you can see the key hole just above the thumb piece, and I don't even object to the MIM parts too much. But I do dislike the full lug under barrel, and the factory grips are cheap and hideous.
Of course, I favor the old Smiths. Of all the 22 revolvers on this page, this well worn K-22 Outdoorsman with its incorrect Magna grips, has the best trigger and is the most accurate of the bunch. It shipped in 1932. Surprisingly, it only cost me $500 a few years ago, a lot less than you will pay for a new 617. The old ones are still out there, but you may have to keep a sharp eye out to find a bargain like this one.
There are of course smaller 22 Rimfire revolvers that S&W makes. The first of the side swing cylinder 22s was the tiny M frame 22 Hand Ejector, usually referred to as the Ladysmith. This little seven shot double action revolver was only chambered for 22 Long, not 22 Long Rifle. There were three different versions made from 1902 until 1921. This 3rd Model Ladysmith shipped in 1910. It is shown with a J frame Model 36 to illustrate how small it is.
Smith and Wesson developed the I frame in 1896 as a platform for six shot 32 caliber revolvers. It was smaller than the six shot K frame which came about in 1899. Other than the tiny Ladysmith, and the old Tip Up Model One, S&W had not made any 22 Rimfire revolvers at this point. Around 1911 San Francisco dealer Philip Bekeart contracted with S&W to build 22 Rimfire Target revolvers on the I frame. These became known as the 22/32 Hand Ejectors, 22/32 Bekeart Model, or 22/32 Heavy Frame Target revolvers.
The oversized grips on this 22/32 Hand Ejector are typical of the Bekeart Model.
But the term Heavy Frame can be deceiving with these revolvers. Although they were larger than the Ladysmith, they were smaller than the K-22 which was the first 'full sized' 22 target revolver that S&W made.
These I frame 22 Rimfire revolvers eventually led to the 22/32 Kit Guns. Originally built on the I frame with four inch barrels, The Kit Guns got their name because they were the ideal size to throw into a tackle kit and take along on camping or fishing trips.
This J frame Model 63 22/32 Stainless Kit Gun was made in 1980 or 1981.
