On occasions I also keep a Bersa 9mm handy, loaded either with special EMB ammo or Gold Dot +P+.
Some people don’t know much about 357 SIG and think it’s equal to 9mm +P+ or even a notch worse than good 40 S&W.
This is some performance information found in Wikipedia on 357 SIG.
Because of its relatively high velocity for a handgun round, the .357 SIG has a very flat trajectory, extending the effective range. However, it does not quite reach the performance of the .357 Magnum with bullets heavier than 125 grains (8.1 g), with the same usable barrel lengths, the typical commercial loadings using 125-grain (8.1 g) bullets, fired from a four-inch (102 mm) barrel; a typical commercial .357 Magnum load propels a 125-grain (8.1 g) bullet to 1,450 ft/s (440 m/s), while a typical .357 SIG load propels the same bullet to 1,350 ft/s (410 m/s), with only a usable 2.85-inch (72 mm) barrel. Specialty loads, such as Double Tap Ammunition, are able to propel a 125-grain (8.1 g) bullet to 1,450 ft/s (440 m/s) from a four-inch (102 mm) barrel. Offsetting this general slight disadvantage in performance is the fact that semi-automatic pistols tend to carry considerably more ammunition than revolvers.
Also like the Tokarev, the .357 SIG works well when shooting through barriers. There has been a documented case in Texas where a police officer's .45 round did not penetrate a tractor-trailer's shell, but a .357 SIG round from a backup officer's gun did, killing the suspect inside. The round's ability to penetrate barriers is the main reason for its adoption by law enforcement agencies. However, other documented police shootings have confirmed the round's ability to not over penetrate the body, even though ballistic gelatin shows 16 inches (410 mm) of penetration through heavy clothing (125 grain Speer Gold Dot). The Virginia State Police have had several documented officer-related shootings involving the .357 Sig, and in every case, not only were the felons stopped instantly with one shot (except one who was shot several times while attempting to murder an officer), the bullet either didn't exit the felon, or was stopped in the clothing upon exiting, proving that even at such high velocities, the round when used with adequate expanding hollowpoints will not over penetrate soft tissue. The same department has also reported that attacking dogs have been stopped dead in their tracks by a single shot, whereas the former subsonic 147 grain 9 mm duty rounds would require multiple shots to incapacitate the animals.
The reputation that the .357 SIG round had for losing its crimp (allowing for bullet setback) was partially true when the cartridge was new and ammunition manufacturers were just beginning to produce the round. These problems have since been corrected by major manufacturers. As a result, the round now exhibits nominal setback characteristics, similar to other cartridges.
The bottleneck shape of the .357 SIG cartridge makes feeding problems almost non-existent. This is because the bullet is channeled through the larger chamber before being seated entirely as the slide goes into full battery. Flat point bullets are seldom used with other autoloader platforms because of feeding problems; however, such bullets are commonly seen in the .357 SIG chambering and are quite reliable, as are hollow-point bullets.
One disadvantage of the .357 SIG is that it fires a .355" bullet at higher velocities than most bullets of that caliber are designed for. Very few bullets have been designed specifically for the .357 SIG, and .357 Magnum bullets that are designed for the same velocity range cannot be used due to their slightly larger diameter. Because of this, there are fewer ammunition choices in .357 SIG than one might expect for a cartridge using .355" bullets.
Another potential drawback of the .357 SIG is its somewhat harsh treatment of pistols that are not designed to handle its high pressure that coupled to its case head area yields a for a semi-automatic service handgun cartridge high bolt thrust. Firing .357 SIG through modified pistols that were originally designed to fire the .40 S&W can accelerate wear.
The "Accurate Powder" reloading manuals claims that it is "without a doubt the most ballistically consistent handgun cartridge we have ever worked with."
The SIG-Sauer P229 in .357 SIG is currently the standard issue firearm carried by agents of the United States Secret Service, the Bastrop County Texas Sheriff's Office, the North Carolina State Highway Patrol, Delaware State Police, Rhode Island State Police, Alameda County Sheriff's Office, Virginia State Police, Federal Air Marshals and the Treasury Inspector General for Tax Administration. In most cases, it has replaced 10 mm, .40 S&W and 9 mm loads. In 1995, the Texas Department of Public Safety became the first government agency to implement the .357 SIG. The Tennessee Highway Patrol presently issues the Glock 31 pistol chambered in .357 SIG. The Bedford Heights Police Department (OH) currently issues the Glock 31/32 in .357 SIG.