Why the .40 S&W? When you go to the gun store and tell the man you are looking to purchase a firearm, does he sell you his favorite or does he ask what you will use it for? For years now, I have been championing the idea that a customer is more satisfied with their purchase if you simply ask how they see themselves using it. Where do you plan to keep it? When would you use it? What calibers are you comfortable shooting? These were some of the questions I asked when a friend came to me to recommend a weapon for his first handgun purchase. His only reference up to that point was a work buddy who brought in his .40 S&W over to show him. So naturally he assumed that was the perfect place to start. Instead I asked, “Why the .40 S&W?” Following the 1986 FBI Miami shootout, law enforcement began to reexamine not only what weapon was carried but also the round. The FBI in particular sought to replace their standard issue revolver with a semi-automatic pistol (Semi-automatic pistols provided the obvious advantages of increased ammunition capacity and was much easier to reload during a firefight). Many of the more popular calibers of the time were examined, but there were still an ‘old guard’ who loved and appreciated the .38 Special +P 158 gr. Twenty years of documented performance was a big hurdle to overcome. To win them over, FBI testers developed a series of eight tests that simulated real world events that agent would likely encounter. And if a new cartridge was to be selected, it had to deliver performance superior to the .38 Special +P 158 gr. The practical replacement cartridges were the 9mm and .45 ACP. However, this is where the story gets interesting, Special Agent-in-Charge John Hall of the FBI Firearms Training Unit, offered his personally owned Colt Delta Elite 10mm semi-automatic along with ammunition he had loaded himself. The tests ended with two primary findings with regard to the 10mm: excellent ballistic performance exceeding the .38 Special +P 158 gram cartridge, but a heavy recoil that necessitated reforming the sight picture following each shot. An issue not unheard of in the .45 ACP, it took a strong hand with experience to keep the 10mm under control. The FBI contacted Smith & Wesson to request a cartridge and handgun design that met their desired specifications on the 10mm model for a medium velocity weapon. Engineers at Smith & Wesson recognized that in downsizing the high velocity 10mm meant less powder and more airspace in the cartridge case. Reducing the airspace allowed them to shorten the cartridge to fit a medium frame 9mm handgun. Nearly identical ballistic performance was produced with far less recoil, and the .40 S&W was born. Once introduced to the law enforcement and shooting communities, the new round and handgun was an immediate success. Law enforcement agencies in Australia, Canada and the United States have made the .40 S&W cartridge their round of choice. It possesses nearly identical accuracy, drift and drop to the 10mm, it has greater kinetic energy over the 9×19mm Parabellum all with manageable recoil most shooters will find easy to keep on target.