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-wesson-m-p-pistols/170963-test-9mm-factory-barrel-m-p-40-a.html

[hals1]

Yup, I assume you mean this thread:

http://smith-wessonforum.com/smith-wesson-m-p-pistols/170963-test-9mm-factory-barrel-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.

[TRshootem]

If you need to buy another barrel, then buy the after market like Storm Lake. I own 3 M&P Pro's: Pro 9 5", Pro 9 CORE w/RDS, Pro .40 5". I have swapped barrels from both 9 pro's into the .40 upper and ran them in Steel Challenge, USPSA, and Defensive Pistol matches. Just because....no issues, worked fine.

[anachronism]

Ditch the 40 and go strictly with 9mm. Any advantage the slightly larger bullet diameter may offer you is negated by your recoil sensitivity to it. Sooner of later you'll screw up and mix the calibers and tie up the gun, hopefully only at the range where the stakes won't be as high as they could be on the street. Keep it simple, and quit trying to have it all in one gun. You are totally unlikely to notice any performance advantage between the 40 over the 9mm with similar quality ammo.

[MStarmer]

Yep he's right. Ditch the M&P and get a Sig P320 and an X-change kit. Then you'll get great accuracy, great trigger and the ability to shoot both 9mm and .40 with just a top end and mag change.

[MegademiC]

There are some advantages to 40 outside of performance which is why I kept mine. Also, now I have an mp 9 that's gaurunteed accurate, sad to say.

[richiecotite]

Ditch the 40 and go strictly with 9mm. Any advantage the slightly larger bullet diameter may offer you is negated by your recoil sensitivity to it. Sooner of later you'll screw up and mix the calibers and tie up the gun, hopefully only at the range where the stakes won't be as high as they could be on the street. Keep it simple, and quit trying to have it all in one gun. You are totally unlikely to notice any performance advantage between the 40 over the 9mm with similar quality ammo.

Have you shot an m&p40 full sized? It's one of the softest shooting 40 caliber pistols around. I highly doubt he would forget what caliber he's shooting and "tie the gun up", especially using the SL barrel as its a different color than the stock barrel.

Regardless of the consensus, 40 has some definite advantages over 9. If you want to shoot some uspsa divisions, you need at least a 40. It also makes for a more decent woods gun in many parts of the country that isn't brown bear or moose country. If you have a perceived need for better performance through cars, the 40 beats the 9.

While the 9 is the better choice for protection against 2 legged critters and for most people,
There's still a reason guys like Tom Givens carry a pistol with a bullet diameter that starts with .4...not to mention ammo availability during panics and the cheap price of .40'son the used market.


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[anachronism]

Read the friggin' thread!

The OP said the recoil of the 40 bothered him, and that he is looking at 9mm as a solution. I suggested he not try the multiple caliber route because the potential for loading the wrong ammo in the gun and tying it up is really high in this scenario.

I did not gore your sacred cow, except to suggest that the 40 has little to offer over the 9mm as far as effectiveness. This may have some bearing on the last line of your post.

[hals1]

OP. I can tolerate the recoil of the 40 for a while. I just don't like to shoot it a lot. Also, I live in Wyoming and both my sons live in Colorado. Since CO has a 15-round mag limit, 9mm doesn't work there (17-round capacity). Change it to 40 and it is 15-round; Legal. Besides I have a fair amount of 40 ammo.

[MStarmer]

OP. I can tolerate the recoil of the 40 for a while. I just don't like to shoot it a lot. Also, I live in Wyoming and both my sons live in Colorado. Since CO has a 15-round mag limit, 9mm doesn't work there (17-round capacity). Change it to 40 and it is 15-round; Legal. Besides I have a fair amount of 40 ammo.

Sounds like a good plan then, stupid limits... Like 2 rounds makes any difference...

[packinaglock]

I have an M&P .40 full size and bought oem 9mm and 357 sig barrels for it. I also bought 9mm mags for it. I have ran both 9mm and 357 sig without any issues and was as accurate as I can be. The 357 sig and 40 both use the same mags.

[JCast265]

I simply bought the factory 9mm barrel and dropped it in my 40 with no failures to date. The wall of the factory 9mm barrel is thicker so it locks up nicely.

[waveslayer]

Are y out guys using your 40 mags for the 9mm? or are you buying new 9mm mags once you convert it?

[MegademiC]

Are y out guys using your 40 mags for the 9mm? or are you buying new 9mm mags once you convert it?

9mm mags. One 40 mag worked, the rest would shoot rounds out the top around round 7 while loading.

Fwiw, I have black baseplate for the 40 and fde for the 9s to help keep them straight.

[waveslayer]

9mm mags. One 40 mag worked, the rest would shoot rounds out the top around round 7 while loading.

Fwiw, I have black baseplate for the 40 and fde for the 9s to help keep them straight.
thanks. I will color mine, makes it easy to organize

[richiecotite]

Same here. For practice mags my 9mm mags have orange basepads, my 40s have light blue basepads, all oemfrom SSS.

Never even tried 9mm in the 40 mags or vice versa



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[LoDie]

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.

I have used both the stock S&W barrel and the Stormlake conversion barrel, they both worked and I had no issues. There are tons of others who have not had an issue with either so I say get the one that you can find.

[LoDie]

Are y out guys using your 40 mags for the 9mm? or are you buying new 9mm mags once you convert it?

I bought new mags so that I know there wouldn't be an issue, plus you gain an extra two rounds to fire when at the range :)

[dwhitehorne]

Another 9 shooter with the 40. Got a 9 factory barrel years ago and have way more 9 than 40 through the pistol. I have the older blued mags in 9mm and the newer finish in 40 to tell the difference. David

[Caduceus]

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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Ditto. I haven't put the 40 barrel back. Carried CCW at times with the conversion. Get the proper mags.