Glock 21

Glock
An early "third-generation" Glock 17
Type	Semi-automatic pistol Machine pistol (Glock 18)
Place of origin	Austria
Service history
In service	1982–present
Used by	See Users
Production history
Designer	Gaston Glock
Designed	1979–1982
Manufacturer	Glock Ges.m.b.H.
Produced	1982–present
No. built	5,000,000 as of 2007
Variants	See Variants
Specifications
Cartridge	9×19 mm Parabellum (Glock 17, 17L, 18, 19, 26, 34, 43) 10 mm Auto (Glock 20, 29, 40) .45 ACP (Glock 21, 30, 36, 41) .40 S&W (Glock 22, 23, 24, 27, 35) .380 ACP (Glock 25, 28, 42) .357 SIG (Glock 31, 32, 33) .45 GAP (Glock 37, 38, 39)
Barrels	1
Action	Short recoil, locked breech, tilting barrel (straight blowback for Glock 25 and 28)
Muzzle velocity	375 m/s (1,230 ft/s) (Glock 17, 17C, 18, 18C)
Effective firing range	50 m (55 yd) (Glock 17, 17C, 18, 18C)
Feed system	Box magazine, see Variants for capacities
Sights	Fixed, adjustable and tritium-illuminated handgun night sights

The Glock pistol, sometimes referred to by the manufacturer as a Glock "Safe Action" pistol and colloquially as a Glock, is a series of polymer-framed, short recoil-operated, locked-breech semi-automatic pistols designed and produced by Glock Ges.m.b.H., located in Deutsch-Wagram, Austria. It entered Austrian military and police service by 1982 after it was the top performer on an exhaustive series of reliability and safety tests.

Despite initial resistance from the market to accept a perceived "plastic gun" due to unfounded durability and reliability concerns and fears that it might circumvent metal detectors in airports, Glock pistols have become the company's most profitable line of products, commanding 65% of the market share of handguns for United States law enforcement agencies, as well as supplying numerous national armed forces, security agencies, and police forces in at least 48 countries. Glocks are also popular firearms among civilians for recreational and competition shooting, home and self-defense, and concealed carry or open carry.

The company's founder, engineer Gaston Glock, had no experience with firearms design or manufacture at the time their first pistol, the Glock 17, was being prototyped. Glock did, however, have extensive experience in advanced synthetic polymers, knowledge of which was instrumental in the company's design of the first commercially successful line of pistols with a polymer frame. Glock introduced ferritic nitrocarburizing into the firearms industry as an anticorrosion surface treatment for metal gun parts.