9c conversion to 40c

[M&P45]

I've read over & over about going from the M&P 40 to a 9 with a barrel and mags. Would this work the other way (9 -> 40)?

Seems like it should work, but I've only seen posts about going 40 -> 9.

Sorry if this is a foolish question.


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[robkarrob]

Starting at post #61, I discuss how this conversion will work. Once the barrel fits, all will work fine. Check the parts manual, the 40c and 9c use the same extractor, ejector, and recoil springs. The slides are the same, except for the markings (M&P 9 or M&P 40) and the opening at the top of the breech face where the tang of the barrel fits.

Bob


http://smith-wessonforum.com/smith-...nverted-my-shield-40-9mm-2.html#post136906257

 

[JustAnotherGunGuy]

No, it will not work. There is a slide thickness difference between the 9 and .40. As slight as it might be it does make a difference.

 

[robkarrob]

Why is there a slide thickness difference. The width of the barrels are exactly the same width. So if the barrels are the same width, what would a thicker slide accomplish? We are not talking about huge pressure differences between 9mm and 40 S&W. Now if your moving up to a 50cal, then a thicker slide will likely be mandated. The 40 barrel will fit into the 9mm slide, except not fully into battery until a little material is removed off the sides of the top rear tang of the barrel, not the sides of the chamber.

Bob

 

[Smitty357]

Why is there a slide thickness difference. The width of the barrels are exactly the same width. So if the barrels are the same width, what would a thicker slide accomplish? We are not talking about huge pressure differences between 9mm and 40 S&W. Now if your moving up to a 50cal, then a thicker slide will likely be mandated. The 40 barrel will fit into the 9mm slide, except not fully into battery until a little material is removed off the sides of the top rear tang of the barrel, not the sides of the chamber.

Bob

He is correct by all means.

And as far as the slides being different (thicker), whoever said that. Thats false information, because i have both and have measured both through all of my testing back from September when I originally discovered the 9mm barrel would work in my .40 slide. The only difference is exactly what robkarrob has stated in the above post. If one were to trim the "tangs" down off the .40 barrel, it would easily fit into the 9mm slide. The .40 slide is a tiny bit wider when the barrel sits into battery (which is why the 9mm fits into 40 slide without problems). The 9mm slide is a tiny bit smaller, therefore the .40 barrel is a tiny bit wider. Thats the ONLY difference between the slides and the barrels.

If i had another .40 barrel for my 9mm Shield, i would have already proven the above statement to be correct.

PS: The .40 slide fits on the 9mm frame and is perfectly flush on the sides where slide meets frame. No difference between either slide being on either frame.

 

[remat457]

Can you weigh the two slides and tell us what the weight difference is between the two?

 

[M&P45]

Starting at post #61, I discuss how this conversion will work. Once the barrel fits, all will work fine. Check the parts manual, the 40c and 9c use the same extractor, ejector, and recoil springs. The slides are the same, except for the markings (M&P 9 or M&P 40) and the opening at the top of the breech face where the tang of the barrel fits.

Bob


http://smith-wessonforum.com/smith-...nverted-my-shield-40-9mm-2.html#post136906257

Thanks for the info.
I'm going to look into doing this, just because .40cal is still on the shelves where 9mm is scarce.

Not sure if I'm the right person to be trimming any material off of barrels though. #noob


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[robkarrob]

If you check the attached photo, the area on the 40 barrel that needs to have material removed is the width shown as .425. If you has access to a surface grinder, this would be the best way to grind the metal off, but even I don't have a surface grinder, and I have lots of tools and equipment. The next best way would be to use a bench grinder, 6 inches or larger. Make sure the wheel has a sharp edge and use the side of the wheel and grind .012 off one side and then grind .012 off the other side. The 40 barrel should fit into the 9mm slide, with the right amount of clearance. Then all you would need is a 40 mag and your ready to shoot.

Bob

 

[robkarrob]

If you check the attached photo, the area on the 40 barrel that needs to have material removed is the width shown as .425 and needs to be reduced to .399. That tang is only 1/8 inch wide and an average of about 3/16 inch high. A surface grinder would be the best way to grind the metal off. I have lots of tools and equipment but I don't have a surface grinder. The next best way would be to use a bench grinder, 6 inches or larger. Make sure the wheel has a sharp corner edges and use the side of the wheel and grind .013 off one side and then grind .013 off the other side. The 40 barrel will then fit into the 9mm slide, with the right amount of clearance. All you would need is a 40 mag and you're ready to shoot.

If you have any small machine shops in your area, someone with a surface grinder could do the job in just a couple of minutes. A surface grinder has a table, which holds the barrel and the table moves the barrel to the grinding wheel, which removes the metal. A bench grinder is basically a surface grinder without a table. Your hands hold and move the barrel into the grinding wheel. Going slow and steady, you will get similar results. It is a small area and very little needs to be ground off.

Bob

A old manual surface grinder with a magnetic table, similar to what I used in Tool & Die work. The ones I used were not quite this old. Some were manual moved and others were hydraulic. Top wheel moves the grinding wheel up and down. Left wheel moves the table left and right. Right wheel moves the table in and out. Your now a certified tool room grinder.

 

[M&P45]

That's awesome. Thanks for the info Robkarrob.


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[remat457]

Can you weigh the two slides and tell us what the weight difference is between the two?

Nobody answered, but according to S&W the difference is very small. 9FS vs 40FS is 0.25oz.

 

[handgunner356]

The side walls of the 40 slides along the barrel are thicker to give it slightly more weight, doesn't bother the fit. Has anyone tried to push a 40 round into a 9mm breehface?

 

[robkarrob]

Has anyone tried to push a 40 round into a 9mm breehface?

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Are you saying the 40 will not fit on the 9mm breach face? The 40c and 9c share the same extractor and ejector. The 40 case rim is only .030 inch larger in the diameter than the 9mm rim.

Bob

 

[isaidme1]

Ive been thinking about this too. Im thinking now that 9mm my not be a good choice because everyone has one and all the ammo is gone. So it would be good to be able to convert to 40 and stock some of that ammo as well.

 

[M&P45]

Haven't swapped the barrels yet, but doctored up my EDC a little. (M&P 9c)

Love this handgun. Such a smooth shooter.


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[robkarrob]

I got an email from someone that had viewed my YouTube video: S&W M&P Shield 40 Conversion to 9mm . He said he ordered the 9mm barrel directly from S&W. I replied to him that S&W has all barrels listed with a asterisk (*) : *=Restricted to factory trained armourers

He said he ordered it and they did not ask any questions, just the address where it was to be sent. He emailed me today and said the barrel arrived today. I phoned S&W today at 2:30pm EST. I called 800 331-0852 extension 4125. I spoke to CSR who gave me the following S&W parts numbers:

Shield 9mm Barrel # 42199
Shield 40 S&W Barrel #42185

S&W has not been releasing any parts numbers for the Shields, saying they didn't have a parts listing for them, yet.

The CSR told me they were out of stock on the 9mm barrels, but do have the 40 barrels. He said they were priced at $61.00 each and there was a $6.50 shipping fee.

So I do not know if S&W is selling all the M&P barrels, but I would think if they are selling Shield barrels they should also be selling the FS and Compact barrels. Anyone wanting barrels, please give them a call and let us know your results on this thread.

Bob