<P> Shortly thereafter, the Glock 17 was accepted into service with the Norwegian and Swedish armed forces, surpassing all prior NATO durability standards . As a result, the Glock 17 became a standard NATO - classified sidearm and was granted a NATO stock number (1005 - 25 - 133 - 6775). By 1992, some 350,000 pistols had been sold in more than 45 countries, including 250,000 in the United States alone . </P> <P> Starting in 2013 the British Army is replacing the Browning Hi - Power pistol with the Glock 17 Gen 4, due to concerns about weight and the external safety of the Hi - Power . </P> <P> Glock has updated its basic design several times throughout its production history . A mid-life upgrade to the Glock pistols involved the addition of checkering on the front strap and serrations to the back strap . These versions, introduced in 1988, were informally referred to as "second - generation" models . To meet American ATF regulations, a steel plate with a stamped serial number was embedded into the receiver in front of the trigger guard . In 1991, an integrated recoil spring assembly replaced the original two - piece recoil spring and tube design . The magazine was slightly modified, changing the floorplate and fitting the follower spring with a resistance insert at its base . </P> <P> In 1998, the frame was further modified with an accessory rail (called the "Universal Glock rail") to allow the mounting of laser sights, tactical lights, and other accessories . Thumb rests on both sides of the frame and finger grooves on the front strap were added . Glock pistols with these upgrades are informally referred to as (early) "third - generation" models . Later third - generation models additionally featured a modified extractor that serves as a loaded chamber indicator, and the locking block was enlarged, along with the addition of an extra cross pin to aid the distribution of bolt thrust forces exerted by the locking block . This cross pin is known as the locking block pin and is located above the trigger pin . </P>

When did the glock gen 2 come out