CODE 04-041-963
NAME – HK 21 – 7.62x39mm
COUNTRY OF ORIGIN – Germany
DATE OF MANUFACTURE – 1963
CALIBER – 7.62x39mm
OVERALL LENGTH – 82 cm (32.28 in) without buttstock, 102.1 cm (40.2 in) with buttstock
BARREL LENGTH – 45 cm (17.72 in) without flash hider
RIFLING (TYPE & TWIST) – 4 Grooves, Right-hand twist, 1 turn in 24 cm (9.45 in)
LOAD – 57N231 PS Copper-plated steel jacket spitzer pointed with steel core
BULLET DIAMETER – 7.90 mm (0.311 in)
BULLET WEIGHT – 7.90 g (121 grains)
MUZZLE VELOCITY – 718 m/s (2356 fps)
MUZZLE ENERGY – 2022 j (1492 ft/lb)
WEIGHT (EMPTY) – 7.32 kg (16 lb 2 oz)
WEIGHT (LOADED) – 10.257 kg (22 lb 10 oz) loaded with belt box holding 100-round belt 57N231 ball
WEIGHT (MOUNTED) – 11.127 kg (26 lb 5 oz) with bipod, sling, support grip, loaded with belt box holding 100-round belt of 57N231 ball
WEIGHT (MOUNTED) – 20.427 kg (45 lb 1 oz) with bipod, sling, support grip, on tripod mount, loaded with belt box holding 100-round belt of 57N231 ball
TYPE OF MOUNT – Removable folding bipod
WEIGHT OF MOUNT – 0.60 kg (1 lb 5 oz)
TYPE OF MOUNT – 1100 Tripod Mount
WEIGHT OF MOUNT – 9.3 kg (20 lb 8 oz)
WEIGHT OF SPARE BARREL – 1.7 kg (3 lb 12 oz)
WEIGHT OF SLING – 0.17 kg (6 oz)
WEIGHT OF SUPPORT GRIP – 0.10 kg (3.5 oz)
SIGHTS – Open, iron, adjustable, Front sight – Hooded post, Rear sight, aperture with rotating elevation drum, 100 meters click stops (109 yard) graduated 100 to 1100 meters (109 to 1,203 yards)
OPTICAL SIGHT – ZF 4×24
OPTICAL SIGHT WEIGHT – 0.65 kg (1 lb 7 oz) with mount
OPTICAL SIGHT MAGNIFICATION – 4 Power
OPTICAL SIGHT FIELD OF VIEW – 5 degrees 40 minutes – 10 m @ 100 m (30 ft @100 yds)
OPTICAL SIGHT ADJUSTMENTS – Adjustable for windage and elevation, 6 adjustments from 100 to 600 m (109 to 656 yards)
EFFECTIVE RANGE – 1,200 m (1312 yards)
OPERATION – Delayed blowback, roller locked bolt system, fires from closed bolt
TYPE OF FIRE – Selective, semi and full automatic
RATE OF FIRE – 50 rpm semi, up to 200 rpm full automatic with barrel change
CYCLIC ROF – 750 rpm
FEED DEVICE – Non-disintegrating steel link belt
FEED DEVICE WEIGHT (EMPTY) – 100 rd belt (four 25-rd sections) 0.227 kg (8 oz)
100-round belt box (Empty) – 1.08 kg (2 lb 6 oz)
FEED DEVICE WEIGHT (LOADED) – 100-rd belt 1.857 kg (4 lb 1 oz), loaded with 100 rds 57N231 Ball
100-round belt box (LOADED) 2.937 kg (6 lb 8 oz) loaded with 100 rounds
BASIC AMMUNITION LOAD – Four-100 rd belts (400 rounds)
LOAD WEIGHT – 7.428 kg (16 lb 6 oz)
MANUFACTURER – Heckler & Koch GmbH, Oberndorf/Neckar, Germany
STATUS – Developmental only
SERVICE – Evaluation only