M&P 40 to 9mm conversion questions

[GKC]

OK, this is just to confirm, but if I'm wrong, please give the correct information:

The M&P FS 40 can be converted to 9mm with the FS 9mm barrel and magazines.

The M&P 40c can be converted to 9mm with the Compact 9mm barrel and magazines.

The Shield 40 can be converted to 9mm with the Shield 9mm barrel and magazines.

The 40 and 9mm use the same recoil spring. No other changes are necessary to convert these pistols from 40 to 9mm. Of course you have to use 9mm ammo.

Is the above stated correctly? Can the SD40VE be converted to 9mm with the SD9VE barrel and magazines? No recoil spring change?

When you make the conversion, does it have any effect on your sight set-up?

 

[robkarrob]

The answer is yes to all guns except I do not know about the SD40VE. POI may change slightly, but nothing significant. I have the Shield 40 to 9mm.

Bob

 

[OKFC05]

Can the SD40VE be converted to 9mm with the SD9VE barrel and magazines? No recoil spring change?

NO. The Sigma/SD Series (interchangeable mags WITHIN CALIBER between Sigma and SD) 9mm magazines are more narrow than the .40 mags, so the caliber conversion does NOT work like the M&P Series.

 

[Gunsmart]

Although the M&P changes are supposed to work, you may get some FTE issues and some FTF issues depending on the ammo.

Generally speaking, the 9mm will send a lighter bullet at approximately the speed a .40 s&w does. Therefore the force on recoil spring will be less when you converted to a 9mm. Your probability of failures will increase unless you find a ammo suitable for it.

Bottom line is you should be OK, I would use it for recreational shooting; I wouldn't CC a converted pistol.

 

[GKC]

Bottom line is you should be OK, I would use it for recreational shooting; I wouldn't CC a converted pistol.

That was exactly my plan. I was thinking that I could use 9mm ammo at the range, and carry the 40. Although, these days I can FIND 40 ammo and I can't find (or afford) 9mm, so I may have that plan backwards!

 

[MSG Glenn]

There are many who have conversion barrels, 9MM or .357SIG, who haven't experienced any problems. I'm thinking about doing the same thing myself. I might start with .357SIG as that round uses the same mags as the .40. I'd like to get a factory barrel but I understand they're hard to get but they're cheaper.

 

[Rastoff]

The 40 and 9mm use the same recoil spring.

This used to be true, but isn't anymore.

As I understand it, S&W went to a higher weighted recoil spring for the .40S&W guns. Therefore, you will see a blue spring and a green spring. The green spring is heavier.

I have the green spring in my .40 full sized. I dropped in a 9mm barrel, got a 9mm mag and went shooting. It worked fine, but the ejection of the 9mm brass is weak. I don't trust it for a self defense situation.

I know a source for reasonably priced 9mm. PM me if interested.