The powerful Glock 20 was designed specifically to take advantage of the large 10mm Auto (10x25mm) pistol cartridge, a round developed by Jeff Cooper and introduced in 1983 for use in the "Bren 10" handgun, this itself designed by Michael Dixon and Thomas Dornaus. The cartridge was intended as a more powerful man-stopper while the Bren 10 was intended to be the advanced weapon of choice to fire the cartridge, this accomplished through pure brute force while still retaining a level of accuracy. The Bren 10 failed to take hold and was produced in a small 1,500 production run lasting from 1983 to 1986. Not a company to sit on their laurels, Glock GmbH tried to capitalize on the market need of the new cartridge. As such, the Glock 20 was developed for both security and police forces to take advantage of the cartridge and production began in 1990 with introduction following in 1991. The Glock 20 was also marketed as an accurate and safe hunting firearm for that "finishing shot", noted in advertisements as "A Perfect 10" in reference to its caliber.
The Glock 20 maintained a slightly larger dimension than the 9mm Glock 17, being both longer and wider - brought about by the use of the larger 10mm Auto cartridge. As such, the barrel and slide components were also constructed heavier than those used in her 9mm Parabellum Glock counterparts. The revision meant that only about half of this newer pistol's parts are actually common and interchangeable with the Glock 17. High-tech polymers worked to reduce the inherent recoil of this powerful weapon. The barrel was rifled, right-handed and hexagonal with a length of twist equaling 250mm (9.84 inches) according to Glock publications.
Design was consistent with previous Glock offerings. The pistol featured clean lines with a black finish and typical Glock squared-off slide and trigger guard. The 15-round capacity magazine entered in at the base of the grip like most any other semi-automatic pistol, the base protruding ever so slightly. Action was short-recoil and double-action. Total length measured in at 7.59 inches with the barrel at 4.61 inches. Unloaded weight was a respectable 27.68 ounces.
An optional 10-round magazine was made available.