M&P .40 - 9mm barrel changing

Strongarm6R · August 28, 2011, 12:46 AM

Hey guys, I've been reading this forum for a bit but just got an account so I can post my own silly questions.
I heard from one of those random genius' at the local gun store that the barrel of an M&P 40 can be swapped out with a 357 SIG barrel in order to fire that cartridge. Also that with a 9mm barrel change and magazine change the same result can be accomplished. Is there any credibility to this and if so does S&W sell just barrels?

I'm just a little skeptical because I haven't heard this from anyone before and I'd figure it would be a popular feature to have that kind of flexibility with a firearm. Thanks for any help and education in this.

Don Glock · August 28, 2011, 12:55 AM

http://smith-wessonforum.com/smith-w...-m-p-40-a.html

here's some info. the OP did put a 9mm barrel in his 40m&p despite it's outer dimensions being slightly smaller. personally, i would not do that. but at least you get the pics and measurements he took and posted.

if you want a 9mm barrel for your 40cal, get an aftermarket conversion one, and use it only for the range and not defense. remember, the breechface is machined for the 357sig/40cal case diameter-not the smaller 9mm.

the factory 357sig/40cal barrels are interchangeable and good to go. however, s&w recently stopped offering 357sig m&p's to the civilian market, only keeping a small amount in production for the few LE agencies that issue them.

Strongarm6R · August 28, 2011, 01:33 AM

Thank you much. I must say I learned a lot from that. I hadn't even considered the breachface. The aftermarket Storm Lake conversion does sound like the best way to go. I have a .45 now but as much as I shoot I'm gonna have to find a sponsor or get a 9mm. Lol. And something .40 and 9mm capable sounds pretty good.

Don Glock · August 28, 2011, 01:53 AM

you're welcome

yeah i shoot my 45's the least lol it's probably my favorite round, but costs too much.

with quality ammo like federal HST jhp's, the 9mm is a great defense round too. don't be afraid to buy one for the range and defense.

K-Swift · August 28, 2011, 04:08 AM

Darn, and I bought the M&P 9..., no caliber swap for me....

August 28, 2011, 12:46 AM	#1
Strongarm6R Member Join Date: August 20, 2011 Posts: 22	M&P .40 - 9mm barrel changing Hey guys, I've been reading this forum for a bit but just got an account so I can post my own silly questions. I heard from one of those random genius' at the local gun store that the barrel of an M&P 40 can be swapped out with a 357 SIG barrel in order to fire that cartridge. Also that with a 9mm barrel change and magazine change the same result can be accomplished. Is there any credibility to this and if so does S&W sell just barrels? I'm just a little skeptical because I haven't heard this from anyone before and I'd figure it would be a popular feature to have that kind of flexibility with a firearm. Thanks for any help and education in this.

August 28, 2011, 12:55 AM	#2
Don Glock Junior member Join Date: September 16, 2010 Posts: 1,141	http://smith-wessonforum.com/smith-w...-m-p-40-a.html here's some info. the OP did put a 9mm barrel in his 40m&p despite it's outer dimensions being slightly smaller. personally, i would not do that. but at least you get the pics and measurements he took and posted. if you want a 9mm barrel for your 40cal, get an aftermarket conversion one, and use it only for the range and not defense. remember, the breechface is machined for the 357sig/40cal case diameter-not the smaller 9mm. the factory 357sig/40cal barrels are interchangeable and good to go. however, s&w recently stopped offering 357sig m&p's to the civilian market, only keeping a small amount in production for the few LE agencies that issue them. Last edited by Don Glock; August 28, 2011 at 01:10 AM.

August 28, 2011, 01:33 AM	#3
Strongarm6R Member Join Date: August 20, 2011 Posts: 22	Thank you much. I must say I learned a lot from that. I hadn't even considered the breachface. The aftermarket Storm Lake conversion does sound like the best way to go. I have a .45 now but as much as I shoot I'm gonna have to find a sponsor or get a 9mm. Lol. And something .40 and 9mm capable sounds pretty good.

August 28, 2011, 01:53 AM	#4
Don Glock Junior member Join Date: September 16, 2010 Posts: 1,141	you're welcome yeah i shoot my 45's the least lol it's probably my favorite round, but costs too much. with quality ammo like federal HST jhp's, the 9mm is a great defense round too. don't be afraid to buy one for the range and defense.

August 28, 2011, 04:08 AM	#5
K-Swift Member Join Date: January 30, 2011 Posts: 26	Darn, and I bought the M&P 9..., no caliber swap for me....