<P> On 29 June 2016 the United States Federal Bureau of Investigation (FBI) awarded a contract to Glock to provide new 9 × 19mm Parabellum chambered duty pistols . The solicitation specifications deviated from the specifications of Glock fourth - generation models . </P> <P> In August 2016 the Indianapolis Metro Police Department (IMPD) started training with a batch of Glock 17M pistols . The most obvious difference with the Glock third and fourth - generation models on published images is the omission of finger grooves on the grip . The IMPD issued a Glock 17M voluntary recall following failures encountered while dry firing the pistols during training . According to Major Riddle with the IMPD; "Glock is working to correct the problem and we hope to begin issuing the new (17Ms) as soon as December". </P> <P> In August 2017, Glock presented the "fifth generation" or "Gen5". The revisions centered on ergonomics and improving reliability . Many parts of fifth - generation Glock pistols cannot be interchanged with those of the previous generations . The two fifth - generation models announced were the Glock 17 and Glock 19, chambered for the 9 × 19 mm Parabellum . Some conspicuous changes on the fifth - generation models are: ambidextrous slide stop levers, nDLC (Diamond - Like Carbon) surface finish for barrel and slide, a barrel featuring conventional land - and - groove rifling (called the "Glock Marksman Barrel" by Glock) rather than the polygonal rifling used in earlier models, a deeper recessed barrel crown, omission of the finger grooves on the grip, a flared magazine well, and a reintroduction of a (half moon shaped) cutout on the bottom front of the grip . The locking block pin located above the trigger pin that was introduced in the third - generation is omitted . Many internal parts were less conspicuously revised . "Gen 5" is rollmarked on the slide next to the model number to identify the fifth - generation pistols . The magazines were also revised for the fifth - generation models . The redesigned magazine floor plates feature a frontward protruding lip to offer grip for manual assisted extraction and the magazine follower became orange colored for easier visual identification . </P> <P> The Glock 17 is a 9 mm short recoil--operated, locked - breech semi-automatic pistol that uses a modified Browning cam - lock system adapted from the Hi - Power pistol . The firearm's locking mechanism uses a linkless, vertically tilting barrel with a rectangular breech that locks into the ejection port cut - out in the slide . During the recoil stroke, the barrel moves rearward initially locked together with the slide about 3 mm (0.12 in) until the bullet leaves the barrel and chamber pressure drops to a safe level . A ramped lug extension at the base of the barrel then interacts with a tapered locking block integrated into the frame, forcing the barrel down and unlocking it from the slide . This camming action terminates the barrel's movement while the slide continues back under recoil, extracting and ejecting the spent cartridge casing . The slide's uninterrupted rearward movement and counter-recoil cycle are characteristic of the Browning system . </P>

When did the glock gen 5 come out