Hey Guys, I got a Steiner MPS and put it on my Glock 17 Gen 5 MOS. It was stellar for 1200 rounds. Then something got loose in it. Fortunately Steiner answered my call and immediately took care of me. I'm receiving my new one tomorrow. I'm not hearing anybody else having issues, so I think I just got "lucky." If you want many of the details, they're in videos, but that is the short story.
https://www.youtube.com/watch?v=Q8_2R97eUUw
https://www.youtube.com/watch?v=56t8JhOl-Y4
https://www.youtube.com/watch?v=mSgUIoRK6kQ