I bought a K-22 back in the early 1980s, and loved it. In the late 1980s, however, during air travel, the rear sight blade cracked. I ordered a replacement, but after installing it it would never group anywhere near point of aim again, no matter how low I set the rear sight adjustment (bottoming it out). It shot way high. So I discovered a gunsmith who retired from being an S&W factory gunsmith and gave it to him, explaining the situation. He ordered what he said was the correct rear sight, and installed it. Same problem. I eventually sold it at a loss at a gun show.
Odd that I couldn't get it to shoot point of aim again after the rear sight broke. As it came from the factory, point of aim and point of impact was achieved somewhere in the middle of the rear sight's elevation adjustment range.
