RIFLING (TYPE & TWIST) – 6 Groove polygonal, right hand twist, 1 turn in 30.5 cm (12 in)
LOAD – XM277 Ball Full metal jacket with lead core and steel penetrator tip
BULLET DIAMETER – 5.69 mm (0.224 in)
BULLET WEIGHT – 3.56 g (55 grains)
MUZZLE VELOCITY – 942 m/s (3,091 fps)
MUZZLE ENERGY – 1,582 j (1,167 ft/lb)
WEIGHT (EMPTY) – 7.82 kg (17 lb 4 oz)
WEIGHT (LOADED) – 11.20 kg (24 lb 11 oz) with ammunition box attached loaded with 200 rounds M27-type link belt loaded with XM777 Ball
WEIGHT (MOUNTED) – 12.08 kg (26 lb 10 oz) with bipod, sling, assault grip, and ammunition box attached loaded with 200 round M27-type link belt loaded with XM777 Ball
TYPE OF MOUNT – Removable folding bipod
WEIGHT OF MOUNT – 0.58 kg (1 lb 5 oz)
WEIGHT OF SPARE BARREL – 1.57 kg (3 lb 7 oz)
WEIGHT OF COMBAT SLING – 0.20 kg (7 oz)
WEIGHT OF ASSAULT 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 click stops) graduated 200 to 1200 meters (219 to 1,312 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 – 650 m (711 yards)
OPERATION – Delayed blowback, roller-locked bolt, fires on closed bolt
TYPE OF FIRE – Selective, semiautomatic, and full automatic
RATE OF FIRE – 50 rpm semi, 100 rpm full automatic with barrel change
CYCLIC ROF – 800 rpm
FEED DEVICE – M27-type flexible disintegrating metallic link belt
This weapon, as the version before it (HK23A1) could be switched over from 5.56x45mm to 7.62x51mm by changing the barrel, bolt, mainspring, and belt feed assembly. The change in calibers takes less than a minute, which was of interest to the US Military, but was not a requirement for the SAWs trials. Additionally, the belt-fed 5.56 XM262 can be changed over to a magazine fed weapon (using HK 33 magazines) by changing the bolt assembly, mainspring, and magazine feed well.
The optical sight was not used during the SAW program tests.