I put a factory 9L rear sight on my 22. Works fine. Pushes almost all the way on by thumb pressure and a few taps from a rubber mallet to finish it up. Just take care not to over tighten the set screw once you get the new one set. It is easy to dimple the aluminum slide. Enough to be seen from the bottom of the slide

__________________
S&W 422 M&P40c M&P15 M&P15-22