Buy 357 SIG – 125 gr GDHP – Speer Gold Dot (53918) – 1000 Rounds

The .357 SIG is a bottlenecked rimless centerfire handgun cartridge developed by the Swiss–German firearms manufacturer SIG Sauer, in cooperation with ammunition manufacturer Federal Premium. The cartridge is used by a number of law enforcement agencies and has a good reputation for accuracy.

Developed in 1994, the new cartridge was named “357” to highlight its purpose: to duplicate the performance of 125-grain (8.1 g) it  loads fired from 4-inch (100 mm)-barreled revolvers, in a cartridge designed to be used in a semi-automatic pistol with greater ammunition capacity than a revolver. Performance is similar to the 9×23mm Winchester.Other than specialized competition cartridges like the 9×25mm Dillon (1988), which necked a 10mm Auto case down to a 9 mm bullet, the .357 SIG (1994) was the first modern bottleneck commercial handgun cartridge since the early 1960s, when Winchester introduced a .257 caliber round based on the .357 Magnum, the now obsolete .256 Winchester Magnum (1960). Then Remington introduced the unsuccessful .22 Remington Jet (1961), which necked a .357 Magnum case down to a .22 caliber bullet, and the .221 Remington Fireball (1963), a shortened version of their .222 Remington. Soon after the .357 SIG, other bottleneck commercial handgun cartridges appeared: the .400 Corbon (1996), necking the .45 ACP down to .40 caliber; the .440 Corbon (1998), necking down the .50 AE to .44 caliber; the .32 NAA (2002), necking the .380 ACP down to .32 caliber; and the .25 NAA (2004), necking the .32 ACP down to .25 caliber. Due to its expense, as .357 SIG practice ammo is about twice the cost of 9mm and around 50% more than .40 S&W, .357 SIG never achieved widespread adoption like .40 S&W.

Cartridge dimensions

.357 SIG maximum C.I.P. cartridge dimensions. All sizes in millimeters.

Americans would define the shoulder angle at alpha/2=18 degrees. The common rifling twist rate for this cartridge is 406 mm (1 in 16 in), 6 grooves, Ø lands=8.71 mm, Ø grooves=9.02 mm, land width=2.69 mm and the primer type is small pistol.Several sources have published contradicting information regarding .357 SIG headspacing.This is due to the cartridge having been originally designed as a .357 (9.02mm) round, but then rapidly adapted to the .355 (9mm) bullet. According to the official C.I.P. (Commission Internationale Permanente Pour L’Epreuve Des Armes A Feu Portatives) 2008 revised documents, the .357 SIG headspaces on the case mouth (H2). Some US sources are in conflict with this standard. However, the cartridge and chamber drawing in the ANSI/SAAMI American National Standards also clearly shows the cartridge headspacing on the case mouth. Likewise, US reloading supplier Lyman has published that the .357 SIG headspaces on the case mouth.According to the C.I.P. rulings 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.

Conversion

While it is based on a 10 mm case necked down to accept 0.355-inch (9.0 mm) bullets, the .357 SIG cartridge case is slightly longer than .40 S&W by 0.009 in (0.23 mm) to 0.020 in (0.51 mm) total. Most .40 S&W pistols can be converted to .357 SIG by replacing the barrel, but sometimes the recoil spring must also be changed. 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 (the C.I.P. and the SAAMI pressure limits for .40 S&W are 225 MPa and 35,000 psi), and may not be suitable for use in all .40 S&W-chambered pistols due to the increase in bolt thrust.