Re: Glock 23?
Its more than just the extractor, the whole bolt face is a different size. I have seen people run 9mm conversions in classes before and they have a lot of malfunctions.
If you call Glock or Springfield they actually tell you not to do those conversions, I have talked to both of them about it. They think it is a pretty stupid idea. 40 to .357 sig is okay, but to 9mm they are just totally different setups.