Just going thru a Lyman reloading manual which lists loads with chamber pressures. The average(approximate) pressure developed by the 40 is abt 23000psi while the Sig 357 is 39000psi. The Sig Sauers can convert from one cartridge to the other by changing barrels and little else. What or how is this major change in pressures justified? And what are the other implications? What do you think?
40 S&W V 357 Sig
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ny32182
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I think .40 runs at higher pressure than that. Are you sure about that number?
Pressure doesn't matter, although the .40 does run at higher pressure than 23,000.
Velocity and bullet weight make a difference. The .357 Sig has lighter bullets but runs higher velocities. It seems to be a wash as far as recoil spring and slide weight needs go.
Velocity and bullet weight make a difference. The .357 Sig has lighter bullets but runs higher velocities. It seems to be a wash as far as recoil spring and slide weight needs go.
Jim Watson
Member
Lyman plays it safe with loads for .40 S&W, stopping well short of the SAAMI maximum pressure. My 47th edition shows .40 pressures in CUP, though, and would probably give higher numbers if in psi. I still doubt they would be up to maximum.
My 47th edition has no "supported chamber" warning, although I am told that the 49th does.
My 47th edition has no "supported chamber" warning, although I am told that the 49th does.
ReloaderFred
Member
As Jim Watson points out, some loading data for the .40 S&W has been tamed down, due to unsupported chambers in some firearms.
The 357 Sig isn't just a .40 S&W case necked down. The case was actually engineered from the ground up to contain higher pressure than the .40 S&W. It has a thicker web and lower wall area than the .40 S&W case does. It's also a longer case.
I shoot both calibers, but have to admit that I shoot very little .40 S&W as compared to the other calibers I shoot.
I would equate your question to a similar one about the .38 Super and 9x23 Winchester. Both cases are basically the same on the exterior, but differ greatly on the inside. The pressures the two rounds work at are very, very different, and the cases are engineered to handle the working pressure of each caliber. It's all in the case.
Hope this helps.
Fred
The 357 Sig isn't just a .40 S&W case necked down. The case was actually engineered from the ground up to contain higher pressure than the .40 S&W. It has a thicker web and lower wall area than the .40 S&W case does. It's also a longer case.
I shoot both calibers, but have to admit that I shoot very little .40 S&W as compared to the other calibers I shoot.
I would equate your question to a similar one about the .38 Super and 9x23 Winchester. Both cases are basically the same on the exterior, but differ greatly on the inside. The pressures the two rounds work at are very, very different, and the cases are engineered to handle the working pressure of each caliber. It's all in the case.
Hope this helps.
Fred
joebiplane
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while you on the subject, i am ordering a kahr PM and i have the choice of a 9mm or a PM .40
I think I prefer the .40 providing that there is little difference in recoil from this small pistol. i intend to practice a lot to become extremely proficient and that means i don't want to have a sore hand no matter what advantages a .40 might have over 9mm
i would appreciate any feedback before I place the order friday
I think I prefer the .40 providing that there is little difference in recoil from this small pistol. i intend to practice a lot to become extremely proficient and that means i don't want to have a sore hand no matter what advantages a .40 might have over 9mm
i would appreciate any feedback before I place the order friday
Runningman
Member
The current SAAMI limit on the 40 S&W is 35,000 PSI. The SAAMI limit on the 357 SIG is 40,000 PSI. Some reloading data for the 40 has been tamed down over the years.
ArchAngelCD
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That is correct...
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