Caliber swap with factory barrels

This is a discussion on Caliber swap with factory barrels within the MP Full Size Pistols forums, part of the Smith & Wesson MP Forum category; So, if I read through the other posts correctly...I can buy a M&P40 and a S&W factory 9MM barrel (and 9mm mags) and have a ...


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Old July 23rd, 2012, 04:56 PM   #1
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Caliber swap with factory barrels

So, if I read through the other posts correctly...I can buy a M&P40 and a S&W factory 9MM barrel (and 9mm mags) and have a 2 caliber gun? The dimensional differences between the 40 and 9mm barrel are slight enough not to drastically affect accuracy or functioning/reliability?
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Old July 23rd, 2012, 05:21 PM   #2
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Yes, I hav e a 9mm S&W barrel on backorder from Midway for 66.99 plus shipping, and I'm hoping I am not too far back on the list to get one the next time they get a shipment in. They say 8/10 (8/03 for the .357 Sig barrels -- but I can only afford one at a time, so I' m going for the one that will actually save me money first). The .357 is even easier to use than the 9mm, since the mags are the same, and the .40 mags can jam on the last bullet with 9mm. (Midway's prices are 77.99 for .357 and 88.99 for .40 barrels)
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Old July 23rd, 2012, 05:28 PM   #3
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Storm Lake Barrels & KKM Precision make both replacement 9mm and 9mm conversion barrels.

An OEM 9mm barrel and any 9mm replacement will not lockup in an M&P40 or 357 the same as a conversion barrel, I would not call it safe.

I think anyone who would use a 9mm barrel other than a conversion barrel in a 40/357 is a complete friggin idiot.

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Last edited by jasonuscg; July 23rd, 2012 at 05:51 PM.
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Old July 23rd, 2012, 05:46 PM   #4
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You might want to check the threads on the Smith and Wesson forum, which not only include many posts from people who have done the drop in with factory barrels as well as the results of measurements by micrometer to verify the lockup on the 9 mm barrel in the .40 before you call anyone " a friggin' idiot" -- an "ad hominem" attack, please!

Many have safely run hundreds of rounds, some thousands of rounds -saving not only the difference between .40 cal. and 9 mm ammo, but also the difference between a $ 66.99 factory barrel and a $150 to $ 200 StormLake barrel.

Last edited by bobnieder; July 23rd, 2012 at 05:48 PM.
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Old July 23rd, 2012, 06:16 PM   #5
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Quote:
Originally Posted by bobnieder View Post
You might want to check the threads on the Smith and Wesson forum, which not only include many posts from people who have done the drop in with factory barrels as well as the results of measurements by micrometer to verify the lockup on the 9 mm barrel in the .40 before you call anyone " a friggin' idiot" -- an "ad hominem" attack, please!

Many have safely run hundreds of rounds, some thousands of rounds -saving not only the difference between .40 cal. and 9 mm ammo, but also the difference between a $ 66.99 factory barrel and a $150 to $ 200 StormLake barrel.
Defending a questionable action with suggestions alluding to checking information on an forum doesn't give me any confidence in another persons position.

Contact S&W, I have, ask them about running an OEM 9mm barrel in a 40/357. I have also contacted Storm Lake regarding use of their 9mm replacement barrels vs their 9mm conversion barrels in a 40/357. Should I also inquire with KKM?

Needless to say none of them are going to honor a warranty under conditions wear a standard 9mm barrel is used in a 40/357 let alone assume any liability.

I started my first post before the one quoted above was posted, it wasn't directed at any particular person, but if someone takes it as an attack, then so be it.
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Old July 23rd, 2012, 06:57 PM   #6
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Ok, since you' re taking the warranty road here, what about the aftermarket mods, including Apex Tactical trigger mods. Are you going to extend your "friggin'idiots" umbrella to cover allof us who have modified our M&P's with these products? What are the boundaries? Because Smith is unwilling to stand behind a combination of their own parts, in a configuration that they use every time they manufacture a 9 mm M&P -- does that even make sense to you? Check the part numbers -- the slide, the recoil spring, the trigger loop, the sear block, in fact every single part in the pistol, except the mags and the barrel, is exactly the same in the .40 and the 9 mm. The .357 only differs from the .40 in the barrel. S&W built the .40 first, it was the prototype, and they gave it enough headroom to handle the higher pressure of the .357, and the 9 mm was an easy step same OD barrel, different bore -- they had already done it with the .357 -- add a mag designed for the smaller 9 mm round, and voila! 9 mm!

I've already expended more energy on this than it's worth. It's really a pretty simple issue. It's not like I'm advocating using Acme Noname 9mm barrels -- they are factory S&W barrels. Of course, I suppose all the people who have posted are lying or delusional -- as are the reviewers on Midway's site that relate that they are pleased with how easily the barrels were to use and how well they functioned.

I am done. You can now sit back and wait for the report of an M&P KABOOM! and for me to say, "If only I had llistened . . . But . . . It's not gonna happen!
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Old July 23rd, 2012, 07:24 PM   #7
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I can guarantee the slides ARE NOT the same between the 40/357 and the 9. Try putting a M&P40 or M&P357 barrel in an M&P9. Try it, then come back with a full report. I'll have a nice hot plate of crow waiting.
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Old July 23rd, 2012, 10:08 PM   #8
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Quote:
Originally Posted by bobnieder View Post
results of measurements by micrometer to verify the lockup on the 9 mm barrel in the .40
The guy who made those measurements intentionally left out measurements that didn't prove his point, setting up folks for a potential failure. Shame on him for doing that, and for repeating it here.

The 9mm factory barrel does NOT lock up properly in the 40 slide and it has contributed to multiple failures including early unlock and cracked/broken barrels.
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Old July 24th, 2012, 08:07 AM   #9
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Quote:
Originally Posted by KRWeiss View Post
The guy who made those measurements intentionally left out measurements that didn't prove his point, setting up folks for a potential failure. Shame on him for doing that, and for repeating it here.

The 9mm factory barrel does NOT lock up properly in the 40 slide and it has contributed to multiple failures including early unlock and cracked/broken barrels.
Perhaps that was the post I saw here or on the S&W forum, I know it was someone saying the had mic'd out everything and there was only a few thousandeths differences in a few places. You are saying this is not correct? and the aftermarket caliber swap barrels are the better choice, albeit more expensive.
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Old July 24th, 2012, 08:26 AM   #10
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Quote:
Originally Posted by robotoid View Post
... there was only a few thousandeths differences in a few places. You are saying this is not correct?
Not just incorrect, it was a deliberate deception.

Quote:
... and the aftermarket caliber swap barrels are the better choice, albeit more expensive.
If S&W made a factory 9mm conversion barrel it would sell for well under $100. Unfortunately they don't, so we have to rely on the match grade aftermarket for 9mm conversion barrels, and match grade is always more expensive.
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Old July 25th, 2012, 07:58 AM   #11
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Quote:
Originally Posted by KRWeiss View Post
The 9mm factory barrel does NOT lock up properly in the 40 slide and it has contributed to multiple failures including early unlock and cracked/broken barrels.
I havnt seen info on this. Do you know where the cracks or breaks are happening?
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Old July 25th, 2012, 01:24 PM   #12
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All were the previous barrel design, as far as I know they all broke right at the notched ring (haven't seen pictures of every one and descriptions vary). By my count at least 9 M&P9 barrels have broken, 4 of those in a 40 slide. I doubt the percentage of folks using a M&P9 barrel in an M&P40 slide covers that spread.
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Old July 25th, 2012, 02:02 PM   #13
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SW-MP-9MMC-425
$121.82 + $5.99 Flat Rate S&H ($127.81)

Grabagun.com Storm Lake Barrels SW-MP-9mmC-425 S&W M&P Online Gun Store
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Old July 30th, 2012, 06:52 AM   #14
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'splain it to me Lucy

I too am interested in this topic, as I am considering such a purchase, so will jump in here with my comments.

I have read a lot of reports from many users in several different forums, that have used the stock OEM 9mm barrel in their 40 S&W without any reported issues. I have not read one reported failure or comment of it not fitting or working properly.
Several people who bought the aftermarket brand barrels have reported multiple issues, from not fitting at all to FTE/FTF and other problems, some requiring multiple trips back to the manufacturer.

There have been more than one person who posted comparative dimensions between stock S&W 9mm & 40 barrels, showing the close dimensional similarities. It appears that most dimensions are within a couple of thousandth's. I said "close" because we must realize of course that there are going to be some measurement variances due to manufacturing tolerances, equipment used and the skill of the person measuring their sample barrels, however the dimensions reported are close enough to being the same as to convince many such as myself, that it will work just fine (who are not experienced gunsmiths in what is/is-not acceptable dimensional tolerances/differences for acceptable barrel fitment).
I have not found any comparative dimensions from owners of aftermarket barrels.

The only negative comments I've seen have been unsupported statements like the ones in this thread. The naysayers commonly just say it won't work and might cite lockup issues but I cannot find any statement indicating where exactly the incompatibility or critical dimensional difference is. I looked up that broken barrel thread and can't see where it relates to using a 9mm barrel in a 40 slide. I would initially say that there was another type of material failure.

When an unknown poster on another forum has supposedly provided supporting facts to their opinion, calling them an idiot or that they were intentionally deceptive, without stating opposing facts makes the name calling and subsequent opinion totally irrelevant in my book. It takes any credibility I had from the dissenting poster and makes me wonder if they have a connection with one of the barrel makers or other vested interest in steering people away from the OEM product.

To help me (and others) understand this issue, I have a couple specific questions I would like answered from those who (act like they) know the facts.

1. What or where is the dimensional incompatibility between the S&W OEM 9mm & .40 barrels that make a 3rd party product necessary for conversion purposes. Don't just cite lockup, explain the lockup process coherently in detail - what, where and why.

2. What are the critical dimensional differences of a 3rd party barrel from the OEM product that are required for conversion compatibility. (Please note if the design difference is related to only for avoiding patent infringement).

3. What are generally accepted tolerances in the various critical areas?

There are many people here who have multiple versions of M&P pistols and some with aftermarket barrels. I suspect there are bonafide pistol-smiths and qualified machinists among us who could answer these questions without a lot of trouble. In my searches, I had hoped that by now, someone with the skill and resources to provide a definite, in-depth answer to this long running and often asked question, would have done so by now. It doesn't look like anyone has. Any takers to this challenge??

So far, I have not seen any real reason not to buy a S&W barrel.

At least over on the XD forum they can tell you that the hole in the end of the .40 slide is too big to allow a stock 9mm barrel to lock up properly and you need a conversion barrel because of the larger diameter.

SG

Last edited by SyberGunner; July 30th, 2012 at 07:06 AM.
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Old July 30th, 2012, 06:58 AM   #15
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I too kept getting conflicting answers. So I emailed S&W directly and asked. Here's the email and replies.
~~~~~~~~~~~~~~~~~~~~~

Hi Stromm
Sorry for the confusion and that would be no to your other questions
Tom

-----Original Message-----
From: [mailto:]
Sent: Thursday, July 26, 2012 5:02 PM
To: Rivers, Tom
Subject: Re: M&P9/357/40 barrel swaps?

Hi Tom,

That answers one of my questions...

Not intending to be rude, but what about the other questions?

Sent from my iPad

On Jul 26, 2012, at 4:22 PM, "Rivers, Tom" <trivers@smith-wesson.com> wrote:

Hi Stromm
You can buy a M&P 357 sig barrel for a M&P 40 cal.
Best regards Tom

-----Original Message-----
From: [mailto:]
Sent: Wednesday, July 25, 2012 6:19 PM
To: Smith & Wesson Support
Subject: M&P9/357/40 barrel swaps?

Please settle a debate going on over at MP-Pistol Forum.

I own a M&P40 (love it too, almost 2000 rounds thought it in six months and not a single issue).

Can I buy a standard M&P9 barrel and magazine and safely use them in my M&P40 frame and slide?

Can I buy standard M&P357 barrel and safely use it with my M&P40 frame, slide and magazine?

If I owned a M&P9, could I safely use a standard 40 or 357 barrel with its frame and slide?


Thank you very much for officially clarifying this debate.

Sent from my iPad
~~~~~~~~~~~~~~
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