There are more reasons than low bid why this 16-shot .40 leads in US police handgun sales. More police departments seem to have adopted the Glock 22 than any other make and model. For years, the FBI has given new agents their choice of a 16-shot G22 or the slightly smaller 14-shot Glock 23.

From the frozen wasteland patrolled by the Alaska State Troopers to the 120-degree streets covered by Phoenix PD, the Glock 22 is standard issue along with numerous other state police agencies and countless sheriff’s departments.

There are good reasons why the Glock 22 is as ubiquitous today in law enforcement as the Smith & Wesson Model 10 M&P .38 Special revolver was when we were younger. Yes, cops buy on bid, and yes, the polymer frame Gaston Glock popularized greatly reduces the cost of the pistol. However, the market is now glutted with polymer handguns.

To understand the G22’s popularity, we have to go back to the time of its birth. The year is 1990. From FBI on down, as the wave builds to sweep away the old service revolver and replace it with the semiautomatic pistol, firearms instructors and rank-and-file cops are split right down the middle. Roughly half want firepower and, at the time, firepower meant a 16-shot 9mm auto such as the Beretta 92, the Sig P226, or the S&W 5906, all extremely popular back in the day.

But the other half want stopping power, colloquially characterized as “a caliber beginning with the number 4,” and that means a .45 auto with typical cartridge capacity of eight rounds. FBI’s John Hall, head of the Firearms Training Unit, has attempted to cut that Gordian knot with a compromise gun, the 10mm Auto, for which S&W gets the fateful and controversial contract. The Bureau decides on a mild subsonic load, 180-grain bullet at a bit under 1,000 feet per second.

At Smith & Wesson, Tom Campbell, Paul Liebenberg, and Ed Hobbe realize these ballistics can be duplicated in a shorter cartridge based on Liebenberg’s wildcat Centimeter round, short enough to fit a 9mm envelope and allow a double-stack magazine giving more ammo in a pistol of reasonable frame size. They approach Winchester, and the result is the .40 Smith & Wesson, debuting in January 1990 at the SHOT Show. It exactly splits the difference between the 16-shot 9mm and the 8-shot .45 paradigms — S&W’s Model 4006 will hold 12 .40 rounds.

Gaston Glock, at the show, sees the round and is intrigued. He orders a version of his tremendously successful Glock 17 9mm built around this cartridge. The first try off the drawing board is too weak for the powerful .40’s vicious slide velocity, and the frame needs to be reinforced. The second incarnation is the charm, and sales take off.