Japanese Type 97 20mm Anti-tank Rifle

Today’s article comes to us from, Christopher Bailey, who is particularly interested in finding information and photos of these kinds of antitank weapons.  He is especially interested in high-quality photos, both period and modern. If you have access to that type of information, please let us know and we will put you in contact with him.

九七式自動砲: The Japanese Type 97 20mm Anti-tank Rifle

by Christopher Bailey

In the middle part of the 1930’s, it became apparent to nearly all observers that another war was on the horizon.  Recalling the lessons of the First World War, nations around the world each began their own program to design and perfect a man-portable anti-tank weapon.  The most obvious solution at the time, and the one that most designers chose as their starting point, was the World War One German concept of an “anti-tank rifle”.  The first such gun, the Mauser 1918 Mauser T-Gewehr, was itself simply a scaled up Model 98 rifle.  Chambered for a newly developed 13mm round, the T-Gewehr was a capable and effective battlefield rifle, and further development of this line of weapons was a reasonable solution at the time.

From this prewar “arms race” came a number of competing designs, amongst them the Polish Wz-35, the German PzB 38, the British Boys Rifle as well as the Solothurn series of commercial guns.  These rifles, all using different mechanisms, show off a variety of design compromises.  Some used a small high-velocity bullet fired out of a light weight gun, while others used a large projectile fired out of an equally heavy weapon.  The middle ground (that of a medium sized round) was also employed, though it was largely overlooked by most designers  Not  to be left behind by these European developments, the Empire of Japan began its own program in 1935, culminating in 1937 with the adoption of the Type 97 Anti-tank rifle.

Type 97 as employed, with magazine and ammunition
Type 97 as employed, with magazine and ammunition



Japanese Type 97 field stripped
Type 97, field stripped. Top to Bottom, left to right: Lower with adjustable legs; barrel assembly; backplate with recoil springs and guide rods; recuperator assembly; bolt carrier with bolt; receiver; charging handle; armor shield; pair of seven round magazines.

Chambered for the powerful 20x124mm cartridge, the Type 97 is a magazine fed, gas-operated weapon that fires from an open bolt.  More like a small artillery piece than a traditional self-loading rifle, the whole receiver and barrel assembly of the Type 97 actually slides front-to-back during firing.  While designed only for semiautomatic fire, there are reports of guns firing fully automatic.  These seem to be either mechanical malfunctions or simply accounts of the Type 98, a fully automatic machine cannon derived from the Type 97.

When fully assembled with its armor shield and carrying handles, the gun weighed in at an astonishing 150 pounds.  Unlike other heavy designs that came equipped with wheeled mounts or skis, the Type 97 was carried by its crew much like an injured man on a stretcher.  This heft, coupled with the guns accessories and ammunition would have certainly place a large burden on the nine man crew during cross country operations.  The barrel, which could be removed for long distance transport, was locked to the receiver using an interrupted thread mechanism.

Type 97 carry handles
Like the Type 92 Heavy Machine gun, the Type 97 came with a set of carrying handles. Note the large, hollow muzzle brake mounted on the end of the barrel to reduce the gun’s felt recoil.
Type 97 barrel locking threads
Front view of receiver with barrel removed. The large interrupted thread is used to secure the barrel into position with a locking collar. The two smaller holes are for the the gas system and its moving parts.

Once the gun had been carried to its destination, the crew would adjust the three legs and lower the weapon into its firing position. To cock the weapon, the charging handle located on the left side would have to be pulled fully to the rear, with a loud “click” letting the shooter know that the sear had engaged the bolt carrier.  After ensuring that both dust covers were open, a loaded magazine would then be locked into place on the top of the gun.  At this point, the gun was ready to fire.

Type 97 charging handle
The charging handle lacks any sort of mechanical advantage, such as a crank or a ratchet mechanism. Brute strength and the use of both hands were required to cock the gun. Note the spring-loaded dust cover, protecting the gun against the ingress of dirt and debris. Hinged dust covers were also fitted over the magazine opening and the ejection port.
Type 97 safety lever
In addition to a traditional trigger safety, the Type 97 was fitted with a bolt-catch safety on the right side of the gun, capable of locking the bolt in the rear position. The upper symbol is for “fire”, while the lower indicates “safe”.
Type 97 magazine, disassembled
The seven round magazine is of a traditional pattern, with a spring-loaded follower forcing the rounds into the feed lips.
Type 97 magazine and round counter
The follower operates a bolt catch on the gun, while the magazine body has a small counter visible only from the rear of the gun. The magazine body itself features two sets of numbers. It is believed that the higher number would match the serial number of the gun, while the single digit number indicates which magazine it is within an issued set.

After loading the weapon, the gunner would lay the gun on his target.   This was accomplished using a rear peep sight and a blade front sight.  Traversing the gun was actually somewhat difficult, requiring the gunner to lift the rear of the heavy gun with his shoulder before shifting it left or right.  Elevation could be adjusted in the similar manner, or by raising and lowering the rear monopod leg via its knurled grip.  An assistant gunner would grip both forward legs to steady the gun during the firing, a position that must have been unnerving to those so assigned.

Type 97 sights
The front and rear sight, the latter of which is adjustable for both range and windage/lead. While the front sight has a winged guard, the rear is rather exposed, allowing it to be easily snagged and damaged. The gun is comfortable to sight on target, with the leather cheek rest and large sight offset permitting the wearing of a helmet.
Type 97 sight picture
A view from the gunner’s position on the Type 97, showing both the protection and the blind spots afforded by the 8mm thick shield. The plate exhibits no visible markings, and is of riveted construction.

Once the gun had been appropriately sighted, the trigger would be pulled firmly to the rear, releasing the bolt carrier assembly.  Driven forward by spring pressure, the bolt would strip a round from the magazine, feeding it into the chamber.  The bolt carrier, continuing forward, would lock the action by forcing a locking piece into cutouts located in the sides of the receiver.  Once fully locked, the firing pin would be struck be the carrier assembly, firing the cartridge.

Type 97 bolt carrier
Bolt carrier assembly in the locked (top) and unlocked (bottom) positions. The locking piece is forced up and down by wedge and cam on the bolt carrier. In the lower shot, the rear of the firing pin is visible between the bolt and the locking piece.
Type 97 locking mechanism
Cutaway drawing of this type of mechanism. The Type 97 actually features two gas pistons, rather than the one in this illustration. The hardened steel locking lugs in the receiver were held into place with screws, making them replaceable if needed.

As the projectile traveled down the barrel at 2,640 feet per second, some of the propellant gas was diverted into a regulated gas tube assembly located underneath the barrel.  The gas acted directly against two integral gas pistons on the bolt carrier, forcing the bolt assembly to the rear and unlocking the gun’s action.  The fired case was then extracted by the bolt and thrown out the bottom of the gun by an ejector mounted in the top of the receiver housing.  Once fully to the rear, the sear would again catch on the bolt carrier, locking the action open until the trigger was pulled once more.  Simultaneous to this internal action, the whole barreled action would cycle both forward and to the rear, its movement being slowed by the recuperator system mounted in the lower receiver.  This additional complexity served to somewhat soften the recoil experienced by the shooter.

Type 97 gas regulator
The gas adjustment valve on the barrel of the Type 97. The gas is bled off into a pair of large gas tubes that are permanently attached to the barrel assembly. Adjustable for ammunition or battlefield conditions, the gas system featured many stainless steel parts for both corrosion resistance and durability
Type 97 recuperator
The adjustment nut on the recuperator assembly. The lug protruding from right side of the tube rotates up into the receiver when fully assembled, locking it onto the lower half of the gun during firing. The large opening functions as the ejection port.
Type 97 tool pouch
The gun easily disassembles for cleaning and transport, requiring only a barrel wrench and a few punches. These were all issued in the gun’s tool kit, along with and spare parts pouch and gun cover.

Production of the gun began in 1938 at the Kokura Arsenal, a facility best known for its small arms production throughout the Second World War.  First seeing combat against the Red Army at the Battles of Khalkhin Gol in 1939, the Type 97 proved to be a disappointment to the Japanese military, with its 20mm round performing poorly against Soviet BT series tanks.  This is somewhat surprising given the fact that wartime American testing demonstrated that the projectile could pierce about 30mm of armor at 250 meters range.

When one also considers the complexity of the gun and the difficulty of manufacture, it isn’t surprising that production of the gun was terminated in 1941 after some 1100 had been completed.  As the war turned against Japan in 1943, the Nihon Seikosho Company (Japanese Steel Works) tooled up and produced another 100 guns, after which no more were made.  Despite its limitations, the Type 97 continued to be a front line weapon throughout the war in the Pacific, usually being employed in a prepared static defense position.  Very few examples of the gun survive today in either private hands or museums, almost certainly due to its bulk and great weight.

Type 97 20x124mm ammunition
The 20×124 round, as used in the Type 97. The wooden blank on the left is believed to be for wartime training. The cartridge on the right is an armor-piercing tracer, for use against tanks and other armored vehicles. The 2500 grain projectile was propelled with approximately 585 grains of nitrocellulose. Included in the cartridge case with the powder was a small sheet of lead foil designed to help reduce fouling of the barrel. Each round was packed in its own cardboard tube before being sealed in a metal lined wooden shipping crate.
Antitank cannon cartridges
A group photo of contemporary antitank cartridges. Left to right: 20x138b (as used in the S18-1000 Solothurn), 20×124 (as used in the Japanese Type 97), 14.5×114 (as used in the Soviet PTRD and PTRS), .55 caliber round for the Boys Antitank Rifle, 7.92×107 (as used in the Wz-35) and the 7.92×94 “Patronen 318” (as used in the PzB 38 and PzB 39).
Type 97 receiver markings
Markings visible on the subject Type 97. As read, top to bottom: “Kokura Factory, Type 97, #418, Showa 15.3 ( March 1940)” This section of the receiver also contains the mechanical bolt safety and can be removed as an assembly.


Technical Specs

Caliber: 20 x 124mm
Mechanism: Gas-operated open-bolt semiautomatic
Length, firing position: 82.5 in (2096 mm)
Length, traveling position: 99.5 in (2527 mm)
Weight, complete: 150 lb (68.1 kg)
Weight, less shield and handles: 115 lb (52.2 kg)
Barrel length: 41.875 in (1064 mm)
Rifling: 8 groove
Magazine capacity: Seven rounds
Muzzle velocity: 2,640 feet per second (866 m/s)
Total production: Approximately 1200