357 Sig Ammunition

The .357 SIG pistol cartridge (designated as the 357 Sig by the SAAMI and 357 SIG by the C.I.P.) is the product of Swiss-German firearms manufacturer SIG Sauer, in cooperation with the American ammunition manufacturer Federal Cartridge. 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 by 0.009 in (0.23 mm) to 0.020 in (0.51 mm) total. The cartridge is used by a number of law enforcement agencies (LEA) and has a good reputation for both accuracy and stopping power.