M&P40 converting to 9 - downsides?

[Cabadam]

I have been thinking about pulling the trigger on a M&P9 lately, but was doing some reading about the M&P40 and converting it to 9mm. It seems to be as simple as getting a 9mm barrel (assuming you can find one) and 9mm magazines. So now I am considering that route too.

But one thing I have not seen discussed much - what are the DOWNSIDES to doing this? I assume there must be, or else S&W would virtually never sell a M&P9?

 

[OKFC05]

The barrel generally works, but does not quite fit the same as the original caliber.
The downside for the company is that they cannot guarantee it will work and assume no responsibility if it does not.

At the range, I have no problem with people shooting them, but personally would not consider a conversion for personal defense or competition.
Also, I prefer to get a gun fitted and worn in, and leave all the parts in it until it needs work for excessive wear, which is a LOT of shooting. So I have a whole gun for .40, and another whole gun for 9mm.

 

[MSG Glenn]

I've heard pros & some cons about the conversion to 9MM. I have a friend who did it with his 40C & uses it that way very often. He had & has no problems whatsoever. I also have an out of state friend who I haven't heard from for a few months who converted his FS 40 to .357Sig & now I think he carries it often with the conversion after considerable range time - I think he said something like close to a thousand trouble-free rounds.

 

[gdnagle]

I would use the .9 barrel for practice cheaper, but still practice with the .40 also. Use the .40 for carry as that's what it was designed for and just use the .9 for practice until you are perfectly satisfied it will perform flawless. Then you have two firearms in one. I've heard more saying they haven't had a problem with the conversion then with it. Just keep the barrel, spring and magazines for each and your good to go.

Here's a old thread about the conversion I imagine it will apply to all.

http://smith-wessonforum.com/smith-...torm-lake-40-9-compact-conversion-barrel.html

 

[DocSunShine]

Get a storm lakes barrel with 9mm mags and you'll be good to go. The extractor and ejector are exactly the same in both calibere... Thr one caveat is if you buy a .40 with a GREEN recoil spring it will be a bit stiff for weaker 9mm loads and should buy a BLUE spring but that is an easy enough fix. My CORE 40 came with a green spring but my FSS 40 came with a BLUE spring (blue is/was universal for .40 and 9mm), but some .40s have been coming with the green spring which works well with .40 but was previously reserved for the .357sig.

 

[DocSunShine]

And it should be noted both the 9c and 40c use the yellow recoil spring so again conversion barrel and mags are all that is required.

 

[Cabadam]

Thanks for the responses.

To clarify - I'm looking at the full size, not compact.

 

[Vinney47]

Yes, if you get a .40 there is the fantastic ability to be able to shoot many calibers in one frame (albeit at an increased cost) but you still only have one gun. Might as well dedicate it to a caliber and if you want to be able to shoot multiple calibers have multiple guns.

 

[DanTana]

I bought the .40L Core and later bought a Storm Lake 9mm barrel which fit loosely in my gun and it had numerous feeding and ejecting issues. I returned it and bought a KKM barrel and it fits even tighter than the stock S&W .40 barrel does and shoots fantastic. I would recommend a KKM barrel if you go that route. I see no downside other than the cost. You get basically two guns for one. 9mm for practice and the .40 for serious business. They both shoot identical, at least in my gun they do. I bought the threaded 9mm barrel which gives it that tactical look to it.

 

[tectrry]

I have a 40c that I shoot more as a 9 than a 40. I usually go through 8-10 magazines at the range with the 9 barrel and then another 4 magazines with the 40. So I keep the 40 barrel in for home defense and as soon as my CCW is approved I will carry as a 40. But I probably have 1500-2000 rounds of 9mm through it and maybe 800-1000 of 40. I use a stock S&W barrel and bought 9c magazines.

 

[Rastoff]

I have a .40 full size. I bought a factory 9mm barrel and a couple of 9mm mags. I've put about 200-300 9mm rounds through it with no issues. The ejection is weak witht he stock recoil spring. So, if I were going to use it for self defense or competition, I'd get a 9mm recoil spring to make the exrraction/ejection a little more reliable.

Otherwise, there's no downside.

 

[Robotech]

I would recommend going with an actual 40-9 "conversion" barrel unless all you want to do is "play" with the 9mm. I wouldn't use the standard 9mm barrel in the 40 slide for any serious or critical shooting.

I've gone with complete barrel and slide sets in 40 and 9mm, so I can shoot either, but I did try the 9mm barrel in the 40 slide. I DO NOT like the sloppy lockup you get. Yes, it works, but I just can't see it as being consistent or reliable enough.

 

[bikendan]

i agree about getting the actual conversion barrel.
i see no downsides to getting the 40 and then a 9mm barrel and mags.
i've had my 40FS for a year now and had the storm lake conversion barrel for almost 10 months.
i've had nearly flawless usage shooting the 9mm. only had a couple of issues with the steel case Tulammo 9mm rounds.
takes only a couple minutes to do the conversion.

i start off shooting the 9mm for awhile and then switch back to 40 cal.

i picked the 40 FS specifically for this capability. now if only 357 Sig ammo would get cheaper, then i'd get the 357 Sig barrel!

 

[turbo38gn]

A+ on the S/L barrels. I have several for my 40fs and 40c, including a ported 357c barrel to go with the 9mm conversion barrels. They have all performed pretty much flawless. I see no downsides to using them other than finding ammo for either one..

 

[pickupman250]

only down sides I can see is cheaper to shoot, easier to control, and only one gun to reg.

 

[snatale42]

only down sides I can see is cheaper to shoot, easier to control, and only one gun to reg.

Reg? As in registration? Ouch!

Sent from my SGH-T999 using Tapatalk

 

[pickupman250]

yeah we have to register everything here now. even 1994 prebans

 

[vegasgunhand]

I have two FS .40s. I also have a factory 9mm and .357 Sig barrels. The 9mmworks pretty well with factory high velocity ammo, but with lighter FMJ loads, I occassionally have a FTE.

The .357 Sig is literally just drop in the barrel and shoot. I've had zero problems when shooting .357 Sig ammo.

 

[snatale42]

yeah we have to register everything here now. even 1994 prebans

That sucks, you guys really got the shaft. I remember when I lived in MA saying "let's move to CT, they don't get screwed with down there". Who would ever think that MA would wind up being a better state for gun owners? For NOW at least, I'm sure that'll change soon enough.

 

[DocSunShine]

I bought the .40L Core and later bought a Storm Lake 9mm barrel which fit loosely in my gun and it had numerous feeding and ejecting issues. I returned it and bought a KKM barrel and it fits even tighter than the stock S&W .40 barrel does and shoots fantastic. I would recommend a KKM barrel if you go that route. I see no downside other than the cost. You get basically two guns for one. 9mm for practice and the .40 for serious business. They both shoot identical, at least in my gun they do. I bought the threaded 9mm barrel which gives it that tactical look to it.

Sounds like you got a bad SL barrel, but I've heard nothing but good things with KKM barrels. I'd really love to see the Bar Sto barrels hit market. Randy Lee mentioned the 40 to 9 conversion bar Sto barrels would likely be available after the 9mm & .40 barrels arrive.