A Japanese 7.7-mm machine gun, Model 97,* mounted in a Japanese light
tank has recently been examined. The bolt and piston assemblies were missing. The
examination disclosed that this weapon was patterned after the Czech ZB (Brno) light
machine gun and the British Bren light machine gun; but the parts
are not interchangeable as the dimensions differ slightly.
The Japanese, tank-mounted, 7.7-mm machine gun, model 97, is an air-cooled,
gas-operated, magazine-fed weapon used with a ball and socket type mount. The
ammunition is fed through an opening in the top forward part of the receiver from
a vertical, staggered, box-type magazine. The sights are offset on the right side
of the weapon because of the position of the magazine. The barrel is of the quick
detachable type but cannot be used as such while in the tank because of a mounting
ring which clamps around the barrel, and gas-piston sleeve. This mount acts as
a base for the mount aligning pins and a swivel ring base for the telescopic sight.
The barrel change lever is on the right side of the weapon.
The portion of the barrel forward of the mounting ring is enclosed in a
hinged steel jacket. The purpose of this is to prevent injury to that part of the
barrel which extends outside of the tank.
The shoulder piece is mounted on a pivot which allows it to be dropped out
of the way when not in use. It is adjustable as to length and is held in one of four
positions by a spring catch located on the underside of the stock.
This machine gun has a ground mount, consisting of a light bipod which is
fitted to the barrel after the detachable armored jacket has been removed.
|Weight w/o magazine or jacket**|| ||23 lbs 6 oz|
|Weight with jacket**||30 lbs 9 oz |
|Overall length||46 1/2 in |
|Length with shoulder piece folded ||39 7/16 in |
|Weight of barrel ||7 lbs 14 oz |
|Length of barrel ||23 11/32 in|
|Rifling||4 lands, 4 grooves, uniform RH twist|
|Front sight ||Tapered post |
|Rear sight||Aperture type |
|Range adjustment||Drum type, graduated to 1,500 m|
|Windage adjustment ||None|
|System of feed||Vertical, staggered, box-type magazine|
|Ammunition||Standard Japanese Model 99 7.7-mm rimless only|
*Mod 97 (1937) 7.7-mm tank machine gun shown without barrel protective jacket
**Minus the bolt and piston assemblies