I have a Gen 3 G22, and have been thinking about doing short term/temporary conversion to 9mm. Do to a diffrent project, I have a completed Gen 3 G17 upper with no home at the moment, along with some 9mm Mags. I am planning on using it for the purpose of plinking/practice (not defense). I do have extra 9mm ejector's, but do not want to go through that hassle switching it back and forth between 40 and 9. As I see it there are 2 basic options, but ultimately I am not sure that there is much of a difference in reliability. I wanted to see what those with more experience in converting have to say. Option 1: - Just swap the completed uppers back and forth whenever I want to change calibers, and make sure I use the correct mags. This will leave me using a 40 ejector, but not sure that it is any diffrent than option 2. Option 2: - Buy a conversion barrel, and just swap the barrels back and froth to change calibers. I would think this would may be less reliable than option 1, since option 1 at least has the correct extractor. Thanks for your input!