Created in an attempt to merge power and high round capacity by combining the speed of a 9mm round with the heavier bullet of a .45 ACP, the .40 S&W pistol cartridge was introduced in 1990 by Smith and Wesson.
The .40 S&W has become a huge success among law enforcement agencies in the U.S because it adds nearly 50% more energy than a 9mm parabellum round, while retaining nearly identical accuracy, drift and drop, yet it still has a more manageable recoil than the 10mm.
The .40 S&W has a muzzle velocity of 985 ft / sec to 1,190 ft / sec, and a impact energy of 400 to 490 ft lbs. The .40 S&W was originally designed to be a "light" 10mm for the FBI to use. Today, .40 S&W has become a popular round and ammunition is generally fairly easy to come by.