FN Five-seven - Design Details

Design Details

The Five-seven is a semi-automatic delayed blowback pistol chambered for FN's 5.7×28mm ammunition. The pistol appears hammerless, but it has a concealed hammer. Polymer materials are used extensively in the pistol's design, and even the steel slide is encased in a polymer shell. In addition to providing reduced weight and greater resistance to corrosion, this also prevents unwanted light reflection. The slide's polymer shell gives the pistol the appearance of being constructed entirely of polymers, but the slide interior, barrel, trigger, springs, pins, and similar parts are all steel. However, the pistol is unusually lightweight, weighing only 744 g (1.6 lb) with a loaded 20-round magazine.

The Five-seven is a full-size pistol, having an overall length of 208 mm (8.2 in), a height of 137 mm (5.4 in), and a max width of 36 mm (1.4 in). It has the same grip angle as the distinguished Browning Hi-Power and M1911 pistols. Despite the considerable length of the pistol's 5.7×28mm ammunition, the grip is not particularly unwieldy—the distance from the trigger to the back of the grip measures 69.85 mm (2.75 in), which is identical to a U.S. Military issue M9 pistol chambered in 9×19mm Parabellum. The Five-seven barrel is cold hammer-forged and chrome-lined, with a total length of 122 mm (4.8 in) and a rifled length of 94 mm (3.7 in). The barrel has eight rifling grooves with a right-hand twist rate of 1:231 mm (1:9.1 in), and it weighs 113 g (0.25 lb). It has a stated service life of 20,000 rounds and the Five-seven is noted for being very accurate.

Current models of the Five-seven are single-action, having a short and light trigger pull of 2 to 3 daN (4.4 to 6.6 lb_F). They have a Picatinny rail for mounting accessories, and a magazine safety mechanism that prevents the pistol from firing without a magazine inserted. The grip texture on current pistols is extensively checkered for a superior hold, and each side of the slide has a series of narrow ridges at the rear to aid grasping. The trigger and trigger guard surfaces also have grooves to reduce finger slip, and the trigger guard is elongated to ease firing while wearing gloves. The Five-seven is currently offered in two different frame finishes (standard black or flat dark earth), and two different iron sight systems (adjustable sights or low profile fixed sights).