Over the weekend I bought a 357 sig barrel for my M&P40. Today I called S&W to see if I needed a stronger spring and just double checked to make sure the barrel "drop in" was all I needed. S&W's customer service rep said they "are not even compatible" and that companys that sell the barrels for conversions need to stop because they won't work. I stated that it was a factory barrel and her reply was" no, they won't work together". Is this b.s. to sell more guns or is there any truth to it?

That's odd. Everything I ever heard or read about the .357 Sig was that it was a complete drop in installation as it's just a necked down .40S&W. I spoke with a TX DPS captain about this when they made the switch from .40S&A to .357Sig and he said their armorer said they really didn't have to even change the magazines, or even the whole pistol, just the barrel. He indicated the reason for switching pistols and magazines was primarily to avoid any potential mistakes and/or liability issues. If it were me, I'd call S&W back in the morning and try to talk to someone else. I had briefly considered a .357Sig barrel for my .40S&Ws, but I really like the 180gr. factory loads, as do my pistols.

Good luck,

Dave

This is BS to sell more guns.

Recoil spring on all the full size M&Ps (other than the M&P45) are the same. If you notice the mags are marked .40 S&W/357 Sig.

The individual you talked to hasn't got a clue. I acquired a 40 M&P in 2007 and a factory 357 barrel shortly therafter. Both are completely interchangable, as are the magazines. I did have to slightly tweek the rear sight for the 357 ammo to zero in. The recoil springs are the same. This topic has been addressed before in this forum. Midway and Brownell's both list factory barrels in their parts lists. Bob

Listen to Bob, especially the first sentence. I just got off the phone with one of the more knowledgeable parts guys at S&W and he assured me it was a drop-in conversion. The barrels are still not available though.....

This feels like one of those questions where you get your head bashed for being stupid, but.........
Why would I want to have the 357 and the 40 as well since they are so close. Is it just muzzle velocity or something else?
What is the purpose?
I really do not know or I would not be asking.
Thanks for being kind to a newbie.
I have the S&W M&P40 and I really like the way it feels.
PW

PWells:

Welcome to the forum. When the TX DPS made the switch from the .40S&W to the .357Sig it was because they felt the .357Sig gave them the performance they were looking for - a .357 round that would equilibrate their favorite issued round: 125gr. JHP. At least this was the story I was told. Most Troopers I know were not happy with the switch, especially as the new pistols (Sigs) were DAO only.

Regards,

Dave

Some officers carry the 357 pistols(be it a Sig, Glock, or M&P) by choice. Most agencies issue 40 ammo for training and carry, but most haven't made the jump to 357 Sig ammo( I was fortunate to work for one that did). If one has both barrels, one could train with 40 ammo and carry the 357 Ranger Talons on duty or for Concealed carry. Forty ammo is usually cheaper and more readily available than 357 Sig. It's sorta like the 38/357 revolver thing. Besides how can you go wrong with one gun that shoots two kinds of ammo. It's like getting a second gun for the price of the barrel!!BTW, I've been using the 357 Sig since its introduction. I've found it easier to get the pistol in 357 and then locate a 40 barrel instead of the other way around. Bob

To both Dave and Roadranger I thank you for your response. I am learning a lot from this forum and looking at all of the areas as I learn.
PW

TX DPS has not ever issued the .40S&W. They went from .357mag revolvers,to 9mm (P-226) or .45 (P-220), to .357 Sig (P-226), to .357 Sig (P-226 DAK).

quote:

Originally posted by Double-O-Dave:
PWells:

Welcome to the forum. When the TX DPS made the switch from the .40S&W to the .357Sig it was because they felt the .357Sig gave them the performance they were looking for - a .357 round that would equilibrate their favorite issued round: 125gr. JHP. At least this was the story I was told. Most Troopers I know were not happy with the switch, especially as the new pistols (Sigs) were DAO only.

Regards,

Dave

arb123 is correct, tx DPS switched from a .45 acp SIG P220 (issued load was a 200 Gr Speer GDHP) to a tradional DA/SA SIG P226 in .357 SIG. .40 S&W was never an approved choice. (357 Sig loads hace been Speer, then remington golden saber bonded) The switch to the DAK action Sig wasn't until 10 years later.

At the M&P armorers course I attended with S&W, thw 357 T&E gun they had was an M&P 40 marked weapon with a 357 barrel. They also specifically mentioned that the conversion was a barrel switch only.

arb123 and car541:

Thank you for the correction. I used to work for the US DOT and we had a working relationship with the TX DPS. I know the officers I worked with carried the Sig P220 in .45ACP. I could have sworn they also had the Sig in .40S&W as an issue weapon, but I must have been mistaken (it's been several years). Sorry for any confusion or misunderstanding.

Regards,

Dave

U talked to a guy I know at S&W about a week ago about the conversion... he said it is not approved nor recommended, but works just fine...

FWIW

Chuck

It probably isn't approved because they wish to sell more guns.I have learned thru personal experience with S+W customer service that some representatives are very knowledgeable and some are clueless....Much like any profession.....God Bless.....Mike