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6.5 mm Heavy Machine Gun Model 3 (1914)

The Japanese 6.5 mm Model 3 Heavy Machine Gun, a gas-operated, air-cooled, full-automatic weapon with a comparatively low cyclic rate, although obsolescent, is being recovered in small quantities from battle areas. It is similar to the 7.7 mm Model 92, but is chambered for the 6.5 mm cartridge. The gas piston and bolt assemblies, and […]

6.5 mm Heavy Machine Gun Model 3 (1914)

The Japanese 6.5 mm Model 3 Heavy Machine Gun, a gas-operated, air-cooled, full-automatic weapon with a comparatively low cyclic rate, although obsolescent, is being recovered in small quantities from battle areas. It is similar to the 7.7 mm Model 92, but is chambered for the 6.5 mm cartridge.

The gas piston and bolt assemblies, and the barrel and barrel sleeve may be interchanged in the two weapons. However, it is impossible to convert the Model 3 for use with the 7.7 mm ammunition as the strip feed port in the Model 3 is one-eighth of an inch narrower than that in the Model 92.

Various machining cuts found in the internal parts of the Model 3 were eliminated in the later model, to provide for ease of production. The oil reservoir is of slightly different shape and probably has a lower capacity than that of the Model 92. The trunnions are of two diameters. The part of the trunnion which contacts the trunnion bearing in the mount is of smaller diameter than that portion which extends beyond the mount. The head thus formed tends to reduce transverse motion.

The weapon has conventional spade grips provided with two finger triggers fixed integrally with the trigger lever so that either or both will fire the gun. There is no safety device.

Two rear sights are provided: one, a folding ring type anti-aircraft sight, is attached permanently to the rear top of the receiver; the other, a tangent curve, radius arm type, is offset to the right. The latter sight is graduated from 300 meters to 2,200 meters (328 yards to 2,406 yards). It is believed that a cartwheel typefront sight is used, as an adaptor for such a sight is riveted to the front of the cooling jacket.

SPECIFICATIONS

Weight (w/ tripod)         122 lbs.
     (w/o tripod) 61.7 lbs.
Length 47.2 ins.
Sight radius 23.6 ins.
Principle of operation Gas
Feeding device Metal strips
Capacity of feeding device 30 rounds
Cooling system Air
Ammunition types Mod. 38, 6.5 mm ball ammunition
Rate of fire Cyclic — 450-500 r.p.m.
  Practical — 200 r.p.m.
Type of sight Two rear sights: folding ring, antiaircraft type; tangent curve, radius arm type, grad. 328-2,406 yds.
Weight of barrel
Length of barrel 29.2 ins.
Length of rifling 26.4 ins.
Rifling
     Twist Uniform, R.H., one turn in 7.88 ins.
     Form Metford segmental
     No. of grooves 4
Depth of grooves
Width of grooves
Chamber pressure 58,800 lbs. per sq. in.
Muzzle velocity 2,434 ft. per sec.
Muzzle energy
Maximum range 4,376 yds.
Effective range 1,500 yds.
Type of mount Tripod
Elevation -15° to +90°
Traverse 33.5°

Japanese: p. 210.1