Originally Posted by CCWKY

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.[11]