What does .357 SIG mean?

Answer 1

The .357 SIG is a rimless bottlenecked pistol cartridge developed in 1994 by SIG Sauer. While it is based on a .40 S&W case necked down to accept 0.355-inch (9.0 mm) bullets, the .357 SIG brass is slightly longer (0.009-inch (0.23 mm) to 0.020-inch (0.51 mm))

.357 refers to the cartridge having similar ballistics to 125 grain .357 Magnum revolver round. SIG refers to SIG Sauer, the company which developed the cartridge.

The cartridge is not proprietary. Other manufacturers, such as Glock, also offer pistols in this caliber.

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 and may not be suitable for use in all .40 S&W-chambered pistols due to the increase in bolt thrust.

C.I.P. and the SAAMI pressure limits for .40 S&W are 225 MPa and 35,000 psi.

According to the C.I.P. guidelines the .357 SIG case can handle up to 305 MPa (44,236 psi) piezo pressure. In C.I.P. regulated countries every pistol cartridge combo has to be proofed at 130% of this maximum C.I.P. pressure to certify for sale to consumers.

The SAAMI pressure limit for the .357 SIG is set at 275.80 MPa (40,000 psi), piezo pressure.