What specifically did you have in mind? You can put a FS 9 in a FS .40 but not the other way around without cutting either barrel or slide.are m&p barrels interchangeable, m&p9/ m&p9 2.0/m&Pc/ shield 9 M&P interchange within caliber and length only. You can't put a FS in a C or shield./ do any m&p barrels fit the sd9's? NO
I read a post on another forum where a poster posted the m&p9 barrel will fit the sd9, got me to thinking are the barrel lugs the same on all the m&p's?
Oh HECK NO. Maybe you can get an M&P barrel into an SD slide removed, but it does NOT fit. The lugs are NOT the same. The SD mostly interchanges magazines, etc within the SIGMAS.
And while the 4 1/2" FS barrel has the same lugs as the 5" L barrel, they do NOT interchange because of the barrel taper, that has to be the right length for the slide. I
If you want an extended barrel KKM can make one for you that fits the FS frame.