M&P 40 to 9mm

[hals1]

I am sure this has been answered before but I can't find anything but hints.

I have a S&W M&P 40 full size. Recoil is a little snappy for my old wrist. Can I get a Smith&Wesson 9mm barrel for it or do I need to get the Storm Lake conversion barrel? How about the recoil spring/guide rod assembly?

I would like to practice mostly with 9mm and carry as a 40.

Mags won't be a problem as I have an M&P Pro long with several mags, but it's too big to carry anything but open. I do love it though.

[bfk4lyfe]

I had the Storm lake conversion barrel in mine, didn't change the recoil spring and it ran flawlessly.

[Alphasig]

Same here I bought the storm lake barrel for my compact 40. Run great in mine. I bought the 9 mag too.


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[sniperfrog]

I've read on the M&P forums that a S&W 9mm barrel will run just fine in the 40. I have the Stormlake barrel and its run great but I would have rather just bought a factory 9mm barrel.

I've measured my M&P 9 barrel and the Storm lake conversion barrel and cannot find any difference between them.

[Auto-X Fil]

Yup, I assume you mean this thread:

http://smith-wessonforum.com/smith-w...-m-p-40-a.html

[hals1]

Yup, I assume you mean this thread:

http://smith-wessonforum.com/smith-w...-m-p-40-a.html

Actually, I hadn't run across that thread or I wouldn't have asked here. The pictures on that thread are gone though.
Thanks!

[MegademiC]

The od of the 40 barrel is larger so lockup is not as good with a factory 9bbl in a 40. Also, the 9mm conversion bbl take into account extractor dimensions, supposedly.

For recoil spring, do you have blue or green? I have green and ejection was reliable, but weak so I bought a Wolff 16#spring assmebly.

If it's just practice the factory should be okay, but it's not "correct" if that kind of thing bothers you.

[crosseyedshooter]

I use a Stormlake 9mm conversion barrel in my M&P40 5". It cycles great with 124gr, but will occasionally misfeed with 115gr. In my case, there was a POI shift of 1" to the right at 15 yards compared to factory .40 barrel.

[TCB]

I ran a factory 9 barrel in a 40 for a number of years with no issues. My buddy has the pistol now and it's still running fine. The only reason I'd go with an aftermarket barrel is if I was going to have it fitted (my other M&P has a fitted match Storm Lake barrel and is a laser beam...).

[MStarmer]

I'd go with the Storm Lake personally. I have a very new M&P 9mm and still don't get very good groups with it, I don't know if I'd attribute it to the barrel itself, lockup or other factors. But shooting it against my PPQ or P320 it's night and day. Oddly my M&P 40 groups great...

Maybe just try downloading some .40? You can always run a lighter recoil spring.