Howdy Again
Jim Watson is correct. There were two variations of the Pre-War K-22s. The first one was called the K-22 Outdoorsman. Also known as the K-22 1st Model. Made from 1931 until 1940. Serial numbers ran from 632132 to about 682419.
Note the lack of a rib on top of the barrel and the teeny, tiny windage adjustment screw on the rear sight.
The K-22 Masterpiece (Prewar, K-22 Second Model) was only made in 1940 and 1941. Only 1067 were made, making them quite rare. Still no rib on top of the barrel, the difference between the 1st and 2nd Models is the 2nd Model used the new click adjustable micrometer rear sight. No, I don't have one, they are quite rare.
After the war, production of the K-22 Masterpiece started again in 1946. Also known as the Postwar, 3rd Model. Note the rib on top of the barrel and the click adjustable micrometer rear sight. Note the different hammer style, it is a 'short throw' hammer much like the hammer on the rare 2nd Model.
In 1957, Smith and Wesson went to a model numbering system and the K-22 became the Model 17. Pretty much the same as the postwar K-22 Masterpiece. This Model 17-3 has a slightly different hammer, and the barrel is non-tapered, with a wider rib on top. A Model 17 will have MOD 17 stamped on the frame under the yoke. It may have the dash number too, such as MOD-17-3 like this one. Like the venerable Model 10, gunshops often mislable a Model 17, sometimes calling it a K-22. If it has MOD 17 stamped on the frame, it is not a K-22, it is a Model 17.
I took one of my prewar K-22 Outdoorsmen apart today, to see whether or not there was a hammer block inside. Nope, no hammer block. This one shipped in 1932, so it is a pretty early one. This one went back to S&W in 1946 for some sort of rework. When I took it apart this morning there was a fair amount of old hardened oil and gunk inside, so I suspect it may not have been opened up since 1946. Anyway, I gave it a good cleaning and closed it back up again.
Regarding the price of K-22s: Here is the same old 1930s K-22, complete with incorrect Magna grips and lots of wear to the blue. The other side does not look so bad, but I always show this side to highlight what a well worn K-22 looks like. I was at an auction one day and none of the high rollers was interested in this one because of the wear to the blue. So I paid $500 for it. It turns out this old 22 is the most accurate of any of my 22 revolvers, S&W or Colt. Because it is so accurate, and was so cheap, it is my favorite 22 rimfire revolver.
While I'm at it, let's talk a little bit more about firing pins on S&W 22 rimfire revolvers.
The first revolvers S&W made in the 1850s were the Tip Up revolvers. They were all rimfires, chambered for what we would call today the 22 Short, or a 32 Rimfire cartridge. There was no separate firing pin on the Tip Ups, the front of the hammer was chisel shaped and served ignite the rimfire priming
In the Top Break days, S&W was only making centerfire revolvers, there were no rimfires. The smallest chambering for Top Breaks was 32 S&W. Not 32 S&W Long, it had not been invented yet. Firing pins were integral with the hammer, like the hammer on this 38 Double Action Top Break.
The first 22 rimfire revolvers S&W made after the Tip Ups were the tiny M frame Lady Smiths. They were made in 3 different models from 1902 until 1921. This is a 2nd Model Lady Smith, it shipped in 1907.
For the Lady Smiths, S&W reverted to a hammer with an integral firing pin.
Before the K-22 came along in 1931, S&W made the 22/32 Hand Ejectors on an I frame, starting in 1911. These were the first rimfire target revolvers that S&W made. The first were the Bekeart models, named after San Francisco gun dealer Phil Bekeart, who convinced S&W to make some on the 32 Caliber I frame. Two are pictured below along with a K-22, to indicate how much smaller they were than a K-22. The middle revolver has the famous Bekeart style grips, the lower one has standard service grips. The lower one was called the 22/32 Heavy Frame Target model. Heavy frame because it was bigger than a Lady Smith. Remember, the larger K-22 had not appeared yet. The 22/32 Heavy Frame Target model eventually morphed into the J frame 22/32 Kit Gun.
Here is the 22/32 Heavy Frame on the left next to a K-22, showing the flat faced hammer and frame mounted firing pin. No, I am not going to take it apart today to see if there is a hammer block inside.
One more photo, just for fun, showing relative sizes of some S&W 22 rimfire revolvers. Top to bottom, K-22, 22/32 Heavy Frame with Bekeart style grips, 3rd Model Lady Smith.