A few years back, the Caliber that many in the firearm community was talking about was the .357 Sig round.

(Cover Photo Credit: GunBelts.com)

Like so many things in the realm of firearms, the “fad” seems to have died off, but make no mistake; the .357 Sig round is still very much alive and well. Even if the price of the ammunition is still ridiculous.

(Photo Credit: American Rifleman)

The caliber is still around and their are still manufacturers like Sig Sauer and Glock that produce firearms chambered in the High Velocity .357 Sig. Although not widely promoted, the .357 Sig round is still a contender in the realm of modern day firearms in my opinion.

Developed by a pas de deux featuring Sig Sauer and Federal Ammunition in 1994, it’s loosely based on a necked down .40 S&W cartridge – conceptually anyway. The idea of .357 Sig is to launch a .355 caliber bullet form an auto loading pistol a few hundred feet per second faster than a 9mm cartridge can.

In 1994, Sig released the P229 pistol, the first production handgun introduced that was chambered in .357 SIG and specifically designed to handle the higher pressures of that round. According to the Sporting Arms and Ammunition Manufacturer’s Institute (SAAMI), the average pressure for the .40 S&W is 35,000 psi. The .357 Sig has an average pressure of 40,000 psi. That extra 5,000 psi!

Other than specialized competition cartridges like the 9×25 mm Dillon (1988), which necked a 10 mm Auto case down to a 9 mm bullet, the .357 SIG (1994) was the first modern bottleneck commercial handgun cartridge since the early 1960’s.

I have heard so many different descriptors when it comes to the .357 Sig round. Things like:

“…it’s like a .357 Magnum, only just in autoloader form…”


“…It’s like a .40 S&W without the snappy kick back…”

Whatever the rhetoric, the truth is that it is a very well performing caliber with tremendous feed reliability and knock down power.

(Photo Credit: Defensive Carry)

While it is based on a 10mm auto case shortened and 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 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 (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.

I carried a Sig P229 in .357 Sig when I was a housing officer, and I have to say that it was hands down one of the best firearms I had ever owned. The ammunition cost has always been a factor, but if you want a great performing caliber pistol and don’t mind spending the money, .357 SIG is a fine choice.