40 to 9 Conversion

[Smitty357]

9mm to .40 Shield has been done by a few members on here. Slight shaving of the .40 barrel to make it fit into the 9mm frame. But of course much like the .40 to 9mm, it'll perform without issue.

I dont know about the compacts or FS models.

 

[Rastoff]

I installed a 9mm factory barrel in my M&P 40FS and my wife used it the next day to qualify for her CHL.

I would not recommend converting a 9mm pistol to 40. That would require milling the sides of the 40 barrel to fit the 9mm slide, effectively reducing the thickness of the chamber walls. If I wanted that conversion I would buy a 40 slide assembly.

Why do you think that? As I posted above, the exterior dimensions of the two factory barrels are identical. At least for a full sized gun it should be just as easy to convert either way.

 

[AwfAxis]

Rastoff, I was about to do this (40 barrel in 9mm slide), but I took a 40 shell, and tried to fit it into the breech of my 9mm slide. It will slide into the space between the ridge and extractor from the bottom, but not from the top. Sliding in a 40 barrel into the slide, and you can get it to seat ok, but the edge of the brass base just barely allows it to fit.

What this means is that any slop in the chamber to slide orientation may allow the brass edge to strike the ridge on the breech, and either deform the brass, or not allow it to go into battery.

To do this, the breech itself needs some widening.

 

[bigm1717]

a little late to this conversation, but also a new 9 owner, and was curious about the 9 to 40 conversion.is the lower the same? if i got a hold of a 40 slide and barrel and mag will it operate properly? or is it just not cost affective?

 

[sstewart]

Yes, done it. Bought a 357 slide (didn't have 40 slide) and a 40 barrel from Midway shoots as good or better than the 9mm slide and barrel. Cost about $290 though.
Sad to say that S&W doesn't like their customers buying parts, They want you to buy GUNS. They are cutting off the supply of these parts. That is why people like Midway have limited or NO stock these days.

 

[bigm1717]

cool, thanks for the info. gonna shop around, see if i can find anything that will work for what im willing to spend. should have thought about this before i bought the 9, probably would have just grabbed a 40 and a 9 barrel

 

[sstewart]

Hey didn't know any better myself.


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[UpstateNY492]

I know this works on the compacts but will it work on a shield? Also, will they be selling .357sig barrels for the shield?

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[sstewart]

The frame is the same on the 40 & 9 mm Shields. Doubtful on the 357 sig though. Just not enough demand for them to do that


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[Rastoff]

I know this works on the compacts but will it work on a shield? Also, will they be selling .357sig barrels for the shield?

The frame is the same on the 40 & 9 mm Shields. Doubtful on the 357 sig though. Just not enough demand for them to do that

S&W never made a .357 Shield so, there aren't any barrels no matter what. If they had made one, it would probably drop right into a .40 Shield just like it does for the full size.

 

[sstewart]

Sorry I didn't realize this was a Shield specific discussion thread


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[Oldgoat03]

I have a Shield 40 and also have stock 9mm barrel and mags for conversion capbility. It has fired flawlessly in both calibers for many rounds.

I also understand the reluctance of some Shield owners to perform this swap because S&W does not endorse it as safe. Not to mention that stock parts are scarce these days.

NOTE - I just rec'd an email minutes ago from KKM stating the following "We are hoping to have conversion barrels for the shields sometime this coming year." So there is hope on the horizin for those wanting 40 to 9mm conversion capability without anxiety.

OG03