Author Topic: CZ75b .40 s&w conversion "kit" to .357 sig  (Read 7166 times)

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Offline tacamo

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CZ75b .40 s&w conversion "kit" to .357 sig
« on: March 11, 2017, 09:26:54 PM »
There are lots of tidbits on this topic spread around on here regarding this topic.  Much seems to be outdated.  Doesn't seem like this should be so difficult.  Bar-sto shows nothing.  CZC shows nothing but a complete pistol. Cajun sez no.  It's 3/11/17....what is the current situation??

Offline Earl Keese

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #1 on: March 11, 2017, 09:33:46 PM »
There are lots of tidbits on this topic spread around on here regarding this topic.  Much seems to be outdated.  Doesn't seem like this should be so difficult.  Bar-sto shows nothing.  CZC shows nothing but a complete pistol. Cajun sez no.  It's 3/11/17....what is the current situation??
You pretty much nailed it.

Offline Earl Keese

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #2 on: March 11, 2017, 09:37:47 PM »
Actually, if you really want to do it, contact CZC. Get a .40sw 75 of your choice, and they can ream the chamber of an SP-01 9mm barrel and fit it to your gun.

Offline DenStinett

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #3 on: March 12, 2017, 12:09:32 AM »
Easy fix
Buy a 9mm Barrel
http://shop.cz-usa.com/ProductDetail/0420049201_Barrel-9mm-7585

Have it reamed to .357 SIG, and you'll have your Conversion Kit
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Offline cntrydawwwg

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CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #4 on: March 12, 2017, 01:48:22 AM »
Doesn't it depend on which .40 it is? Doesn't the barrel bushing have to match the 9mm barrel?
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Offline Ruber

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CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #5 on: March 12, 2017, 12:01:45 PM »
I have a '14 75B in 40 and a '15 SP01 9mm.  I've thought about this so I tested fit of the Sp01 9mm barrel in the slide and on the frame of the 75B.

The SP01 and 40 barrels had the same OD at the muzzle, but that was about it.  The .40 SW barrel had larger barrel hood, lugs, and cam.  The 9mm sp01 barrel was swimming in the 40 slide and didn't lock up tight at all.  Conversely, the .40 barrel did not fit my SP01 slide or frame. The lugs and barrel hood would not seat into the slide.  Without the slide, the cam/ramp would not fit the frame.

Reaming the sp01 9mm barrel I have would make for a thin walled chamber and a very loose barrel in the .40 sw 75B. 


The lugs and barrel cam are just a tad bit beefier on the .40

I can't make a 40 SP01 to 9 SP01 comparison, the 40 SP01 is still on my wish list...
« Last Edit: October 31, 2019, 01:34:12 PM by Ruber »

Offline huskerlrrp

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #6 on: March 12, 2017, 01:22:16 PM »
CZ custom will do the conversion on a 40 Slide. Call or e-mail them and they can get you a price. It's not as inexpensive as other platforms. I had bought a slide for that intention on a manual safety SP01 but never got around to it and then put my slide up for sale (never sold). I might go back to the project (357 SIG barrel) if I can't get my money out of it.

Offline eastman

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #7 on: March 12, 2017, 03:30:34 PM »
The conversion is straight-forward on an SP-01, because the 9x19 and .40 barrels have the same outside dimensions (I've switched back and forth between them on a .40 SP-01 Tactical). Other CZ pistols won't be easy if the barrel dimensions differ.
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Offline DenStinett

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #8 on: March 12, 2017, 04:43:24 PM »
The CZ75/85 Barrels are different from the SP-01s
http://shop.cz-usa.com/SearchByKeyword?word=sp-01%20barrel
So tell me again how Trump was worse then the 8 years before .... AND what's coming after HIM !

Offline tacamo

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #9 on: March 12, 2017, 07:16:49 PM »
I've contacted cz custom (by e-mail).  We'll see what happens next.  I really hadn't thought about replacing the slide...just the barrel and guide rod spring. I think I would have preferred a .40 barrel (external dimensions) set up for the sig (as in drilled) rather than a 9mm reamed with a sig chamber.  Seems like the heavier .40 barrel would be preferred to handle the ~40Kpsi.  Just thinkin'.

Offline huskerlrrp

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #10 on: March 12, 2017, 09:53:19 PM »
I've contacted cz custom (by e-mail).  We'll see what happens next.  I really hadn't thought about replacing the slide...just the barrel and guide rod spring. I think I would have preferred a .40 barrel (external dimensions) set up for the sig (as in drilled) rather than a 9mm reamed with a sig chamber.  Seems like the heavier .40 barrel would be preferred to handle the ~40Kpsi.  Just thinkin'.

You need to start with a 40 S&W slide as the breech dimensions are the same for the 357 SIG. A 9mm slide won't have the correct machining/size for the cartridge. Therefore you can go 40S&W to 357 SIG but not 9mm to 357 SIG.
The 9mm barrel barrel bore will actually be thicker than the factory 40 since it's the same OD between the two (@14mm OD, 9 vs 10mm ID). If I recall correctly, it is a SP01 dimension 9mm barrel with the chamber machined and reamed to the 357 SIG profile and the bottom lug machined.

Offline DenStinett

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #11 on: March 12, 2017, 10:29:45 PM »
I've contacted cz custom (by e-mail).  We'll see what happens next.  I really hadn't thought about replacing the slide...just the barrel and guide rod spring. I think I would have preferred a .40 barrel (external dimensions) set up for the sig (as in drilled) rather than a 9mm reamed with a sig chamber.  Seems like the heavier .40 barrel would be preferred to handle the ~40Kpsi.  Just thinkin'.
The 40 cal barrel isn't even the right Barrel to start with
As the Bore is WAY TOO large
The .357 Bullets are 9mm not 10mm (40cal)
Yes, you'll need a 40cal Slide
So tell me again how Trump was worse then the 8 years before .... AND what's coming after HIM !

Offline tacamo

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #12 on: March 13, 2017, 09:05:14 AM »
I disagree- the .40 would be the best barrel (blank) to start with.  That way all the external dimensions match the .40 frame.  The assumption on my part has always been that the barrel blank would be drilled, chambered and rifled for the .357.

Offline BubbaLa

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #13 on: March 13, 2017, 08:28:56 PM »
I disagree- the .40 would be the best barrel (blank) to start with.  That way all the external dimensions match the .40 frame.  The assumption on my part has always been that the barrel blank would be drilled, chambered and rifled for the .357.

I don't  think you know how these barrels are made, there's no drilling, rifling , do a Google search on hammer forged barrels.
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Offline DenStinett

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Re: CZ75b .40 s&w conversion "kit" to .357 sig
« Reply #14 on: March 13, 2017, 08:41:02 PM »
I disagree- the .40 would be the best barrel (blank) to start with.  That way all the external dimensions match the .40 frame.  The assumption on my part has always been that the barrel blank would be drilled, chambered and rifled for the .357.
OK, so what you're saying; you are going to buy a Barrel Blank for a .40cal CZ75B, that hasn't ever been bored or rifled in any caliber (maybe (just maybe) CZCustom can supply that to you)
Then find a Pistolsmith that with bore and rifle it to 0.355, and chamber it in .357 SIG (maybe CZCustom will even do this for you)
I'm saying this with all the best intentions.....GOOD LUCK with that !

I think you'd find that the standard (NOT an SP-01) CZ75B 9mm Barrel and the standard CZ75B .40cal Barrel both have the same physical outer dimensions
But I could be wrong
If you call CZCustom or PM Stuart here, he should be able to clarify it all, and give you same solid advice on your best path to take
Again, good luck in your quest


So tell me again how Trump was worse then the 8 years before .... AND what's coming after HIM !