I have used both the Marvel Unit 2 and the Kimber .22 conversion on my Mil Spec Springer. No problems, tight fit and actually some very good for 1911 trigger time at a nice low expense. I can't speak for how they would fit and work on other Springer models.Any body ever put a .22 conversion on their springfield? Springfield recommends against it. Can it be done safely, without damaging the frame? Thank You ina dvance.