BARREL LENGTH – 50.8 cm (20 in) without flash suppressor, 53.3 cm (21 in) with flash suppressor
RIFLING (TYPE & TWIST) – 6 Groove, 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 – 991 m/s (3250 fps)
MUZZLE ENERGY – 1749 j (1290 ft/lb)
WEIGHT (EMPTY) – 3.08 kg (6 lb 13 oz) without sling
WEIGHT (LOADED) – 3.51 kg (7 lb 12 oz) with sling, loaded with 20 rds M193 Ball
WEIGHT OF SLING – 0.11 kg (4 oz)
SIGHTS – Open, iron, adjustable, Front sight – Round post, adjustable for zero range, Rear sight – Leaf-type with apertures for 0-300 m (0-328 yards) and 300-500 m (328 to 547 yards)
EFFECTIVE RANGE – 500 m (547 yards)
OPERATION – Gas impingement
TYPE OF FIRE – Selective, Semi and Full automatic
RATE OF FIRE – 45-65 rpm Semi, 150-200 rpm Full automatic, 12-15 rpm sustained rpm
FEED DEVICE WEIGHT (LOADED) – 0.32 kg (11 oz) loaded with 20 rounds M193 Ball
BASIC AMMUNITION LOAD – Six 20-round magazines (120 rounds)
LOAD WEIGHT – 1.92 kg (4 lb 4 oz)
MANUFACTURER – Colt Patent Fire Arms, Hartford, Connecticut
STATUS – Out of production
SERVICE – US Air Force
This was the original style of M16 rifle, as adopted by the US Air Force. It did not have the forward bolt assist later seen on the M16A1. It did have the 1 in 30.5 cm (12 in) twist rate on the rifling as it was the Air Force who had noted the lack of accuracy of the original rifling twist when the temperature as below O⁰
30 round magazines were perfected and began being issued to the troops in volume in 1970. The weight of the empty 30-round magazine is 0.110 kg (3.92 oz [4 oz])
