Can you do it with a M&P??

[Albee4ty5]

Buy a 9mm barrel for a 40 cal M&P and run it? Will a 9mm magazine fit in the 40 frame? Checking out options. I know with a Glock this can be done. Just wonder if can do it with a Smith M&P as well. And if you can how reliable does it seem to be? Thanks

 

[2238945]

From what I understand it can be done just as easily as with a Glock. The only reason I would need to do this with a Glock would be to get the conventional rifling as I cast and load mainly cast. With the M&P you get conventional rifling right out of the box.

 

[shotslow]

You have to get a 9mm conversion barrel specifically made to function in a 40 S&W M&P. Go to Storm Lake. There are other makers. The 9mm mags will fit in the 40 M&P and visa versa. Even the slide and barrel assemblies interchange. I have both calibers and tested it, but have not fired them. Not going to either.
Did get a 357 sig barrel for the Pro 40. Works like a charm.

 

[remat457]

I know with a Glock this can be done.

As mentioned above only with a CONVERSION barrel. The breechface is different on the slide and hood length. Try Storm Lake, EFK Firedragon, BarSto, etc. Opinions on how well the conversions work seem to vary wildly.

 

[Lost Lake]

Do a search, there are dozens of posts on this. Some members here have swapped factory 9mm barrels into their .40 and run thousands of rounds through them with no problems. There are some here that have mic'ed their 9mm and .40 barrels and they are nearly identical just a smaller inside bullet diameter, and one fellow called S&W and was told they cannot officially recommend swapping the barrels, but then the customer service rep said "wink, wink".

You can get a factory barrel for $65 from online retailers. I think with all the people that have done it, it is worth a try to buy one and see for yourself. Storm barrels have had problems too, so buying a more expensive barrel is not a guarantee of better performance.