The Glock family of pistols, once started by famous Glock 17 pistol, was developed by Austrian company Glock Gmbh., previously known for quality knives and entrenching tools. The Glock 17 pistol first appeared at the Austrian Army trials, won it and was adopted by Austrai Army and Police in the early 1980s under the designation of P-80. Since then, the Glock 17 and its descentants become very popular military and law enforcement firearms, being exported in more than 50 countries. Currently, Glocks are chambered in all major pistol calibers, namely 9x17mm Short (.380ACP), 9x19mm Luger, .357SIG, .40SW, 10mm auto and .45ACP. Also, Glocks available in full-size service models, semi-compact models, compact models for concealed/backup carry, and in longslide competition models. Training versions, firing non-lethal practice ammo, also available. Training versions are distinguished from "live" ones by frame colour - blue frame for guns that fire non-lethal ammunition and red frame - for non-firing guns.
The Glock 19 is effectively a reduced-size Glock 17, called the "Compact" by the manufacturer. It was first produced in 1988, primarily for military and law enforcement. The Glock 19 has a barrel and pistol grip that are shorter by approximately 12 mm (0.5 in) compared to the Glock 17 and uses a magazine with a standard capacity of 15 rounds. The pistol is compatible with factory magazines from the Glock 17 and Glock 18, with available capacities of 10, 17, 19, and 33 rounds. To preserve the operational reliability of the short recoil system, the mass of the slide remains the same as in the Glock 17 from which it is derived. With the exception of the slide, frame, barrel, locking block, recoil spring, guide rod, and slide lock spring, all of the other components are interchangeable between the models 17 and 19.
All Glocks feature polymer frame, steel slides made by precision moulding process and had Tenifer heat-threatment to increase rust and wear risistance. early Glocks had plain grips with slight serrations. Modern variants has finger grooves on the front strap of the grip, and ambidextrous thumb rests. Also, modern versions featured underbarrel acessory rails. Barrels has hexagonal rifling in all calibers. Both front and rear sights are dovetailed and usually had white or luminous inserts. Ajustable sights are available for competition models.
Almost all models had modifications with factory-ported barrels. These models are marked with suffix "C" after the model number, i.e. Glock 17C.
At the 2010 SHOT Show, Glock presented the "fourth generation" design, with updates centered on ergonomics and the recoil spring assembly. The fourth generation models do not have total parts modularity with its predecessors, meaning not all parts can be mixed and matched with previous Glock generations. The initial two fourth generation models announced were the full-size Glock 17 and Glock 22, chambered for the 9×19mm Parabellum and .40 S&W cartridges, respectively. The pistols were displayed with a modified rough texture frame, grip checkering, and interchangeable backstraps of different sizes. "Gen4" is rollmarked on the slide next to the model number to identify the fourth generation pistols.
The basic grip size of the fourth generation Glock pistols is slightly smaller compared to the previous design. A punch is provided to remove the standard trigger housing pin and replace it for the longer cross pin needed to mount the medium or large backstrap. With the medium backstrap installed, the grip size is comparable to the third generation pistols. The magazine release catches are enlarged and reversible for left-handed use. To utilize the swappable magazine release feature, fourth generation Glock magazines have two notches cut on both sides of the magazine body.
Mechanically, fourth generation Glock pistols are fitted with a dual recoil spring assembly to help reduce perceived recoil and increase service life expectancy. Earlier subcompact Glock models such as the Glock 26 have already used a dual recoil spring assembly which was carried over to the fourth generation versions of those models. The slide and barrel shelf have been resized, and the front portion of the polymer frame has been widened and internally enlarged, in order to accommodate the dual recoil spring assembly. The trigger mechanism housing has also been modified to fit into the smaller sized grip space.
The introduction of fourth generation Glock pistols continued in July 2010 when the Glock 19 and Glock 23, the reduced size "compact" versions of the Glock 17 and Glock 22, became available for retail. In late 2010 Glock continued the introduction of fourth generation models with the Glock 26 and Glock 27 "subcompact" variants.
In January 2013 more fourth generation Glock pistols are expected to be introduced commercially during the annual SHOT Show including the Glock 20 Gen4 along with other fourth generation Glock models.
All Glocks (except for ones chambered in 9x17 - .380ACP) are recoil operated, locked breech pistols. Glocks feature Browning-type linkless locking system with barrel interlocking with slide via ejection port. All Glocks feature patented "Safe action" striker-fired trigger mechanism. After the each cycle of the slide the striker is set to half-cock position and is safely blocked by internal safety. When shooter pulls the trigger, he disengades the trigger safety first, then cocks the striker to the full-cock and then fires the gun. This results in constant trigger pull (ajustable from 2 to 5.5 kg) and, unlike the traditional DA or DAO pistols, unavailability of the "second strike" option in case of the misfire. All Glocks has no external controls except the trigger and the slide stop (the only different is Glock 18, which has slide mounted fire mode selector).