Originally Posted by dsf

I'm in CA so buying a new M&P is a challenge, can't be had through the usual FFL dealer stock route. Used ones are expensive - as in $800.00 to $1,000.00, no thanks. I know barrel swaps alone can't go from 9mm to 40 but with a barrel, slide and recoil spring can I go from 9mm to 40?



Found lots of info on what I can't do, nothing on this specifically or why.