Key Point: The Glock 45 is the pistol for Glock owners who approve of the Commander pistol concept and like the improvements introduced in the Glock 19X—but don’t necessarily need the military’s bells and whistles.

The Pentagon’s quest for a new handgun ended in the U.S. Army choosing one handgun, the Sig Sauer P320, to replace the Beretta M9 across the entire armed forces. Although most companies lost, the competition encouraged many companies to enter modified designs that otherwise might never have seen the light of day—designs that are now hitting the civilian market. The Glock 45 pistol is one such design, incorporating a compact slide with a full-size frame to produce a pistol unlike other Glocks.

The U.S. Army’s Modular Handgun System competition saw eight different gun manufacturers in the U.S. and Europe scramble to produce a pistol that fit the service’s requirements. These guns ranged from a modified version of the military’s M9 pistol, the Beretta M9A3, to the Smith & Wesson M&P9. Handgun technology had changed dramatically since the M9 had been picked in the late 1980s, with the use of polymers, improved ergonomics, and other features now standard on civilian pistols. The Army, which oversaw the MHS tests, expected to fully exploit these new technologies in the new pistol.

Glock’s entry into the competition, the Glock 19X, was originally described in outside reports as a direct copy of the compact Glock 19. The Glock 19 is one of the Austrian gun manufacturer’s most popular pistols as many consider the original Glock 17 too large and other Glocks too optimized for concealed carry or larger calibers. The Glock 19 is considered the ideal combination of size and weight, magazine capacity and caliber.

In reality, the G19X was quite different from a standard G19. The G19X featured a shorter, Glock 19-length barrel 4.02 inches long, resulting in an overall length of 7.44 inches. This made a compact pistol more than an inch shorter than the existing Beretta M9.

The real revelation behind the G19X was its adoption of the Colt Commander-style pistol concept. In the early 1950s, Colt’s Manufacturing Company introduced a shorter version of the M1911A1 .45 caliber pistol that retained the pistol’s original grip length. This new pistol, badged the Colt Commander, had a shorter barrel but accepted standard M1911A1 magazines, meaning it retained the same magazine capacity.

The G19X took the Colt Commander concept and ported it to Glock’s 9-millimeter line of pistols. The G19X has an overall length nearly identical to the Glock 19 but a height—largely including grip length—identical to the Glock 17. This gives the G19X the compactness of the G19—especially useful inside aircraft and military ground vehicles—and the ammunition capacity of the Glock 17. This adds two more rounds, for a total of 17, to the Glock 19’s magazine.

After the conclusion of the Modular Handgun System competition Glock—like other entrants—opened the designs up for sale on the civilian market. Glock sells the G19X as it was marketed to the U.S. military, but for those who don’t need a lanyard and their pistol in flat dark earth color there’s the Glock 45. The Glock 45 eliminates these military-specified requirements, trading them for a traditional Glock-style magazine well. (Both the Glock 19X and the Glock 45 also eliminate the Army-mandated manual safety.) The Glock 45 also comes in black and includes a serrated front slide popular with users who like to conduct press checks on their pistols. Finally, the Glock 45 also includes the company’s new Marksman barrel, which offers improved accuracy.

In addition to the Glock 45, Glock has also come out with a modified version, the Glock 45 MOS, or modular optic system. The 45 MOS features a cut in the slide just in front of the rear sights. This cut allows the user to install their own miniature reflex sight, a smaller version of the red dot sights used on military and civilian rifles.

The Glock 45 is the pistol for Glock owners who approve of the Commander pistol concept and like the improvements introduced in the Glock 19X—but don’t necessarily need the military’s bells and whistles. The original Colt Commander concept is seventy years old and going strong, which gives one an idea just how long the Glock 45 may stick around.

Kyle Mizokami is a writer based in San Francisco who has appeared in The Diplomat, Foreign Policy, War is Boring and The Daily Beast. In 2009 he co-founded the defense and security blog Japan Security Watch.