The .357 SIG is a centerfire pistol cartridge developed in the 1990s by SIG Sauer and Federal Premium Ammunition. It was designed to provide a high-velocity round with better performance than the traditional .357 Magnum while fitting in a semi-automatic pistol. The cartridge typically features a bullet diameter of .355 inches and is known for its accuracy and stopping power. This cartridge is commonly used by law enforcement and military personnel due to its effective terminal ballistics. The .357 SIG is often chambered in various handguns, including models from SIG Sauer, Glock, and Smith & Wesson, making it a popular choice for self-defense and tactical applications.