M&P 40 conversion to 9mm

View · by **INOR** on Wed Feb 28, 2018 8:33 pm

Anyone ever convert a M&P 40 to 9 or vice versa? I have a M&P 40 which is my bedside gun but thinking of buying a barrel and some mags and converting to to shoot 9. A lot of my other handguns are 9 and it’s what I prefer to shoot at the range in my semi autos. (Other than my SAR K2 .45, of course!) I often end up not taking the M&P with to the range because I don’t want to bring three or four different calibers of ammo with me.

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View · by **Holland&Holland** on Wed Feb 28, 2018 8:51 pm

No personal experience so maybe someone will come along, but have read on the S&W forums of many folks just doing the conversion with a factory 9 barrel and new mags with no issues. Should be cheap enough to try anyways.

View · by **onebohemian** on Thu Mar 01, 2018 1:39 pm

I did this years ago to a 40c. Went with the storm lake barrel which was brand new at the time. Storm Lake screwed up their first barrels and fitting was required. After I finished it, they admitted their mistake, but I stuck with my work product. Bought 9mm mags and all was good.

The most risky part of doing this is making sure you have the right mags and ammo in the gun for the correct barrel. Obviously 40 won’t fit into the 9 chamber, but vice versa is possible. Just have to be vigilent when packing the range bag.

Good luck,

View · by **azonesolutions** on Thu Mar 01, 2018 7:16 pm

Did a Storm Lake 40 to 9 conversion barrel in a full size M&P two years ago. About 2000 rounds through it without a problem.

View · by **Ghost** on Thu Mar 01, 2018 7:23 pm

Seems like a good reason to buy another gun to me.

I wonder how many people first bought a 40 and ended up getting a 9? I never hear of people going the other way.

View · by **INOR** on Thu Mar 01, 2018 8:27 pm

Yeah, looking back I should have just bought a 9 as that’s what I like but I thought I’d try a 40. And part of it was because I bought it back when ammo was tight and harder to find and I wanted an ability to shoot a variety. Oddly enough at that time, 40 seemed more plentiful on the shelves than 9. I do still like the idea of having the 40 for that reason but i want to be able to shoot 9 through it too.

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View · by **Ghost** on Thu Mar 01, 2018 9:07 pm

INOR wrote:Yeah, looking back I should have just bought a 9 as that’s what I like but I thought I’d try a 40. And part of it was because I bought it back when ammo was tight and harder to find and I wanted an ability to shoot a variety. Oddly enough at that time, 40 seemed more plentiful on the shelves than 9. I do still like the idea of having the 40 for that reason but i want to be able to shoot 9 through it too.

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For the $160 or so a barrel costs plus mags, makes those shield 9mm for $225 seem like a steal.

View · by **INOR** on Thu Mar 01, 2018 9:13 pm

Yep. That shield was a great deal. Love that gun. Now I have an urge to complete the M&P series and get a M&P9c. But I think I’m going to hold off as I really want to see how the Sig P365 does and if they get past their new gun glitches.

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View · by **Holland&Holland** on Thu Mar 01, 2018 10:30 pm

Ghost wrote:Seems like a good reason to buy another gun to me.

I wonder how many people first bought a 40 and ended up getting a 9? I never hear of people going the other way.

I've done that before, couple of times now that I think about it.

View · by **Ghost** on Fri Mar 02, 2018 5:41 am

Holland&Holland wrote:
Ghost wrote:Seems like a good reason to buy another gun to me.

I wonder how many people first bought a 40 and ended up getting a 9? I never hear of people going the other way.

I've done that before, couple of times now that I think about it.

My first pistol was a 40. I never use it anymore. I’m still yet to fire my only semi 9mm though.

View · by **Holland&Holland** on Fri Mar 02, 2018 9:33 am

Ghost wrote:
Holland&Holland wrote:
Ghost wrote:Seems like a good reason to buy another gun to me.

I wonder how many people first bought a 40 and ended up getting a 9? I never hear of people going the other way.

I've done that before, couple of times now that I think about it.

My first pistol was a 40. I never use it anymore. I’m still yet to fire my only semi 9mm though.

I have 2 .40s and shoot them both. Have 7 9s and shoot them too

, My philosophy is own everything, shoot everything

View · by **ZeeC** on Wed Mar 14, 2018 1:02 pm

I have a 9 barrel and I use the 40 mags, rounds are a little looser but no feed problems.

View · by **Aliensrgr8** on Tue Apr 24, 2018 5:28 pm

I purchased a .40 M&P and did a Storm Lake 9mm conversion barrel. I also purchased factory S&W 9mm mags. Since converting my barrel over 3 years ago I have not put my .40 caliber barrel back in it. I have lots of rounds down range with no issues. I too wanted the flexibility to shoot both Calibers as ammo was in short supply. I wish I would have purchased a threaded conversion barrel rather than a normal barrel.