.357 sig in a 40c?
- Thread starter frogman18
- Start date
I second that yep.
I have a M&P40 Pro that I swap between a 40s&w, 357sig & a 9mm conversion barrel (also need the 9mm mags). All three work as well as the factory guns. My neighbor has a M&P9. We both have the 5" barrel versions. My M&P40 with the 9mm conversion barrel shoots & feels just like his M&P9. For a little more money I got the equivalent of 3 guns vs. his one 9mm gun. Not to bad if you ask me.
I have a M&P40 Pro that I swap between a 40s&w, 357sig & a 9mm conversion barrel (also need the 9mm mags). All three work as well as the factory guns. My neighbor has a M&P9. We both have the 5" barrel versions. My M&P40 with the 9mm conversion barrel shoots & feels just like his M&P9. For a little more money I got the equivalent of 3 guns vs. his one 9mm gun. Not to bad if you ask me.
Rangel
Well-known member
Online quotes from Wikipedia: (not the 'end all arguments' authority source):
>>Conversions
>>Most .40 S&W pistols can be converted to .357 SIG by replacing the barrel, but sometimes the recoil spring must be changed as well. Pistols with especially strong recoil springs can accept either cartridge with a barrel change. Magazines will freely interchange between the two cartridges in most pistols. .357 SIG barrel kits have allowed this cartridge to gain in popularity among handgun owners. However, the .357 SIG is loaded to higher pressures than the .40 S&W (the C.I.P. and the SAAMI pressure limits for .40 S&W are 225 MPa and 35,000 psi), and may not be suitable for use in all .40 S&W-chambered pistols due to the increase in bolt thrust.
Developed in 1994, the new cartridge was named "357" to highlight its purpose: to duplicate the performance of 125-grain (8.1 g) .357 Magnum loads fired from 4-inch (100 mm) barreled revolvers, in a cartridge designed to be used in a semi-automatic pistol. Performance is similar to the 9x23mm Winchester.
The .357 SIG provided a self-defense cartridge close in performance to a 125 gr .357 Magnum, but from a semi-automatic pistol with greater ammunition capacity.
The .357 SIG was the first modern bottleneck commercial handgun cartridge since the early 1960s, when Remington introduced the unsuccessful .22 Remington Jet (1961), which necked a .357 Magnum case down to a .22 caliber bullet<<< (end quote)
To confuse things more--while I don't shoot much in the way of the different 38 caliber loads, I 'thought' that if a gun barrel can handle a hot 38P load, that the same barrel can usually handle a 357 load--true or not or just for revolvers? Then again, just as not all 38 caliber bullets are the same, the SIG 357 is a bit diferent in it's own right from other 357s, so there may be a number of variables here and I'd hate for someone to have 'kaboom' by making assumptions from here....
>>Conversions
>>Most .40 S&W pistols can be converted to .357 SIG by replacing the barrel, but sometimes the recoil spring must be changed as well. Pistols with especially strong recoil springs can accept either cartridge with a barrel change. Magazines will freely interchange between the two cartridges in most pistols. .357 SIG barrel kits have allowed this cartridge to gain in popularity among handgun owners. However, the .357 SIG is loaded to higher pressures than the .40 S&W (the C.I.P. and the SAAMI pressure limits for .40 S&W are 225 MPa and 35,000 psi), and may not be suitable for use in all .40 S&W-chambered pistols due to the increase in bolt thrust.
Developed in 1994, the new cartridge was named "357" to highlight its purpose: to duplicate the performance of 125-grain (8.1 g) .357 Magnum loads fired from 4-inch (100 mm) barreled revolvers, in a cartridge designed to be used in a semi-automatic pistol. Performance is similar to the 9x23mm Winchester.
The .357 SIG provided a self-defense cartridge close in performance to a 125 gr .357 Magnum, but from a semi-automatic pistol with greater ammunition capacity.
The .357 SIG was the first modern bottleneck commercial handgun cartridge since the early 1960s, when Remington introduced the unsuccessful .22 Remington Jet (1961), which necked a .357 Magnum case down to a .22 caliber bullet<<< (end quote)
To confuse things more--while I don't shoot much in the way of the different 38 caliber loads, I 'thought' that if a gun barrel can handle a hot 38P load, that the same barrel can usually handle a 357 load--true or not or just for revolvers? Then again, just as not all 38 caliber bullets are the same, the SIG 357 is a bit diferent in it's own right from other 357s, so there may be a number of variables here and I'd hate for someone to have 'kaboom' by making assumptions from here....
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While I don't normally place a lot of faith in Wikipedia quotes you do bring up some valid questions. I am going to look into the spring difference between the M&P 40 & 357sig springs. If S&W offers separate spring strengths for each I may order a 357sig spring to install when I change the barrel. Personally, I have no other concerns about this conversion since the higher pressures will be contained within the converted barrel. I would expect the barrel to withstand the added pressure since that is what it is designed to shoot.
Rangel
Well-known member
If you look at most S&W guns and compare them to other company's similarly priced competition in the same class of gun, I have noted that usually the S&W's are built sturdier. Whether it's revolvers, semi autos or rifles--their metal parts or if it's the case, even their polymer parts, tend to be a litle thicker and beefier than 'they 'have to be'. If you're experimenting with different calibers on the same firearm, for me at least, that gives me a little more peace of mind.
It's kind of odd that the S&W M&P semi autos typically come in a bit lighter in weight than the Glocks or Springfield XD/m of the same caliber, yet to me, they don't seem to sacrifice structural integrity in doing so. if I'm going out for a while and can carry a loaded S&W that's at least as sturdy, reliable and accurate as a competitor's gun, but is considerably lighter, I'll go with the Smithy almost every time.
It's kind of odd that the S&W M&P semi autos typically come in a bit lighter in weight than the Glocks or Springfield XD/m of the same caliber, yet to me, they don't seem to sacrifice structural integrity in doing so. if I'm going out for a while and can carry a loaded S&W that's at least as sturdy, reliable and accurate as a competitor's gun, but is considerably lighter, I'll go with the Smithy almost every time.
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DavidC77
Well-known member
Ya, when I get some money growing on my tree out back I want to get a 357 sig barrel for my M&P 40 FS and one for my M&P 40c.
I just have to wait alittle longer
.
I just have to wait alittle longer
.
BigRich315
Well-known member
Storm Lake finally got around to distributing one, for the longest time a factory barrel was the only way to go. I love their 9mm conversion, so naturally that's the way I'll go for a 357.
DavidC77
Well-known member
None of the distributors had the 5" barrels listed on their sites, so I had to go to the Storm Lake site. 
When you go there you end up paying full retail. My 5" barrels were $160 each there, but I had no choice since no body else knew what I was talking about. 
They have been really good barrels at least.
When you go there you end up paying full retail. My 5" barrels were $160 each there, but I had no choice since no body else knew what I was talking about. They have been really good barrels at least.
