9mm Barrel in a M&P 40

[Mitch Rapp]

Looking to get a 40 or 357 sig M&P, and from what I have read the factory barrels can just "drop in" to swap calibers. Obviously I would need 9mm mags, but is there any issue with reliability, or other things that I am missing? For carry it would stay in either 40 or 357 (to be honest .40 doesn't do much for me, I love 357 sig though).

Anyone tried this?

 

[mike cyrwus]

breechface is different; get a 40 to 9mm conversion barrel.

 

[Wildcat]

I have a 40 M&P Pro and I use a KKM 40 to 9 conversion. It works great! I don't think they are much more then ordering a factory barrel. KKM, Storm Lake, and Lone Wolf are the ones I know of.

 

[SgtDave]

I used a M&P 40 pro with a 9mm pro barrel and it worked fine.

 

[Mattyvip]

I have a standard M&P 40 with a storm lake 9mm barrel. It's been working great.

 

[JohnCea]

I see someone tried that. It works great