[3] The .357 SIG is based on a necked-down 10mm Auto case, forgoing the large pistol primer utilized by the 10mm Auto in favor of the small pistol primer used in many common self-defense rounds, such as .40 S&W, .38 Special, 9 mm and other similarly-sized cartridges.

Excluding specialized wildcat cartridges used in competition shooting — e.g., the 9×25mm Dillon, which necked a 10mm Auto case down to a 9 mm bullet — the .357 SIG was the first modern bottlenecked handgun cartridge to become commercially available since the 1961 introduction of Winchester's now-obsolete .256 Winchester Magnum, a .257 caliber round based on the .357 Magnum.

Because of this, as well as availability issues, some law enforcement agencies that previously adopted the cartridge have reportedly began to move away from the .357 SIG in favor of more common rounds with comparable performance.

(Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portatives) 2008 revised documents, the .357 SIG headspaces on the case mouth (H2).

Because of its relatively high velocity[14] for a handgun round, the .357 SIG has an unusually flat trajectory, extending the effective range.

Offsetting this general slight disadvantage in performance is that semi-automatic pistols tend to carry considerably more ammunition than revolvers.

[19] The Accurate Powder reloading manual claims that it is "without a doubt the most ballistically consistent handgun cartridge we have ever worked with".

[12] The goal of the .357 SIG project was to offer a level of performance equal to the highly effective 125-grain (8.1 g) .357 Magnum load.

[20][21] Measurements of standard factory .357 SIG cartridges loaded with 125-grain (8.1 g) bullets showed approximate muzzle velocities of 1,450 feet per second (440 m/s) out of a 4 inches (102 mm) barrel, which is essentially identical to the .357 Magnum with the same bullet weight and barrel length.

[30] The ability to carry more rounds per magazine (9 mm vs. .357 SIG) in a lighter gun were among the stated reasons for the change.

[31] That transition was suspended after recruits in the A-2014 class, the first to train with the new S&W M&P 9 mm polymer handguns, experienced numerous malfunctions with those weapons.