M&P 40 to 9 conversion

I have been reading on ARFCOM a thread about converting a M&P 40S&W to a 9mm simply by swapping out factory barrels.
Has anyone here tried this yet?

It may work. I certainly would never carry such a monstrosity. You would have to deal with slide mass, recoil spring, and extractor issues that would affect reliability going from .40 to 9mm.

Doesn't 9mm require a different breach face for reliable operation?

I don't know. The OP from the thread mic'd each of the barrels and they were pretty close IIRC.
Here is the thread:
http://www.ar15.com/forums/topic.html?b=5&f=16&t=104694

I'd be interested to know how the factory 9mm barrel compares dimensionally to a Storm Lake 40-9 conversion. The factory 9mm barrel is about half the price of a Storm Lake on brownells midway.

I have a friend I shoot IDPA with who has a M&P40 PRO. He has both a 9MM & 357 Sig Barrel for it. I think all he does is switch barrels and recoil springs. He did install adjustable sights so he could adjust the point of impact across the various loads.

I guess I'll just have to take the leap and try it out for myself. While I wait for 9mm magazines from 44mag.com, I think I'll double check some dimensions with my own micrometer.