I dont think you need to change extractors... I know lots of people who swap 9mm/40 cal barrels. I dont think you need to swap mags - but, it's probably not a bad idea.Anyone try a conversion barrel in their Glock? I have a Glock 23 that's a .40. Its the only .40 I have. The others are 9mm. With the ammo prices the way they are...I figure it would just be easier to use one caliber at the range. My local range doesn't even have reloads in .40.
I'd get a conversion barrel and a couple G19 mags. Would I also need an extractor too? That seems to be 50/50 from the stuff I've read.