CODE 04-041-964

NAME – HK 21 – 5.56x45mm

COUNTRY OF ORIGIN – Germany

DATE OF MANUFACTURE – 1964

CALIBER – 5.56x45mm

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 30.5 cm (12 in)

LOAD – M193 Ball, Spitzer-pointed full metal jacket

BULLET DIAMETER – 5.70 mm (0.224 in)

BULLET WEIGHT – 3.56 g (55 grains)

MUZZLE VELOCITY – 939 m/s (3082 fps)

MUZZLE ENERGY – 1573 j (1160 ft/lb)

WEIGHT (EMPTY) – 7.32 kg (16 lb 2 oz)

WEIGHT (LOADED) – 9.79 kg (21 lb 9 oz) loaded with belt box holding 100-round belt M193 ball

WEIGHT (MOUNTED) – 10.66 kg (23 lb 8 oz) with bipod, sling, support grip, loaded with belt box holding 100-round belt M193 ball

WEIGHT (MOUNTED) – 19.96 kg (44 lb) with bipod, sling, support grip, on tripod mount, loaded with belt box holding 100-round belt M193 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 – Blowback, Delayed 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 – 850 rpm

FEED DEVICE – M27-equivalent disintegrating link belt

FEED DEVICE WEIGHT (EMPTY) – 100-rd M27 links section – 0.21 kg (7.4 oz)

100-round belt box (Empty) – 1.08 kg (2 lb 6 oz)

FEED DEVICE WEIGHT (LOADED) – 100-rd M27 link belt – 1.39 kg (3 lb 1 oz) loaded with 100 rounds of M193 Ball

100-round belt box (LOADED) 2.47 kg (5 lb 7 oz) loaded with 100 rounds of M193 Ball in M27 links

BASIC AMMUNITION LOAD – Eight 100-rd belts (1,000 rounds)

LOAD WEIGHT – 11.12 kg (24 lb 8 oz)

MANUFACTURER – Heckler & Koch GmbH, Oberndorf/Neckar, Germany

STATUS – Production completed

SERVICE – Evaluation