[seamuskrat]

I have a M&P .40. I have read the barrel dot the .357 sig is a drop swap and to covert to 9 is also a simple aftermarket barrel swap and new magazine. Sound right?
I'd love to have multi ammunition capable parts with minimal expense. Loving my.40 so far.

Thanks

[psymmonds]

Yes, yes, and yes. To convert to .357, you just need a new barrel. The .40 mags are modeled for .357 also. Says it right on the mag. 9mm on the other hand, you need a 9mm barrel and mags to go with it. 9mm will fit in the .40 mag but will be a little loose. I myself wouldn't chance it, I would get new mags to go along with it. You can buy S&W factory barrels off of midwayusa. Or you can go to this storm lake.

http://www.storm-lake.com/products/barrel

[robocop10mm]

The .357 mags are exactly the same as the .40 mags. The only "modification" is the stamp.

[sweeper22]

357sig and 40sw are going to be identical apart from the barrel.

When converting down to 9mm you may need an actual '40 to 9 conversion' barrel, rather than just a plain old 9mm barrel. There can be some issues with how the firing pin and primer line up laterally in some guns due to the reduced casing diameter.

[seamuskrat]

Thanks! Now to find them in stock somewhere!

[austin92]

Looking to get an m&p soon and intend on shooting .40 and .357 sig from it but I'm wondering which gun I should buy and which barrel. Like ".357 m&p/.40 barrel" or ".40 m&p/.357 barrel"?

[coinbuyer]

Originally Posted by austin92

Looking to get an m&p soon and intend on shooting .40 and .357 sig from it but I'm wondering which gun I should buy and which barrel. Like ".357 m&p/.40 barrel" or ".40 m&p/.357 barrel"?

Just an FYI They are the same. They literally run and assemble the same gun and then set the barrel to what the frame is stamped. I would look at two things. The price of the aftermarket or factory barrels. Is one cheaper or not. Also availability of the complete firearm. Before the "gun scare" the 40 was very available and inexpensive in the used gun market. Now it seems that when you do find the 357 Sig, it is less expensive then the others.
I would buy the one you could get the best deal on and then buy the other caliber barrel.
My ten cents

[austin92]

Originally Posted by coinbuyer

Just an FYI They are the same. They literally run and assemble the same gun and then set the barrel to what the frame is stamped. I would look at two things. The price of the aftermarket or factory barrels. Is one cheaper or not. Also availability of the complete firearm. Before the "gun scare" the 40 was very available and inexpensive in the used gun market. Now it seems that when you do find the 357 Sig, it is less expensive then the others.
I would buy the one you could get the best deal on and then buy the other caliber barrel.
My ten cents

Good points. Thanks man

[jakil007]

Just got the 4.25 9mm, where / how can I get other caliber barrels? I'm in north Idaho, and local shops seem out of the loop

[Rick1967]

I am suprised that you can swap between 9 and 40. I would have thought that the diference in case size would be a problem for the extractor. I would also wonder if the bolt face on the slide of a 9mm would be big enough for a 40 to fit into. Is this a non-issue then or is everybody just guessing?