Prototype 7.7mm Arisaka Type 99 Carbine

Summary

Ian McCollum examines a Japanese experimental 7.7 mm carbine developed during the trials that led to the Type 99 rifle. The example shown is a rare Nagoya Arsenal trials gun, serial number 4. McCollum believes it is the cavalry-carbine version of “Plan Number 2,” though detailed information about the trials is scarce.

Why Japan developed a new rifle

Japan had long considered replacing its 6.5 mm rifle cartridge with a more powerful one, but development accelerated in 1938. Early that year, Kokura Arsenal converted 300 Type 38 rifles to the new 7.7×58 mm cartridge. The conversions worked without revealing fundamental problems.

In April 1938, the military set requirements for a new standard rifle. It had to:

• Weigh less than 4 kg (8.8 lb).
• Have a lighter stock than the Type 38.
• Be straightforward to manufacture.
• Use an aperture rear sight, an unusual choice compared with the sights on many contemporary military rifles.

The arsenals developed paired long rifles and cavalry carbines, following the Type 38 practice.

Notable features of the experimental carbine

The carbine retained the basic Type 38 Arisaka action but incorporated several distinctive changes:

• Extended, bent bolt handle: A style more commonly associated with sniper rifles, used on both this carbine and its companion long rifle.
• Aperture rear sight: A tangent-style sight adjustable to 1,500 metres, mounted at an unusual angle. The handguard was shaped to accommodate it.
• Revised magazine release: The release was moved from the rear to the front. Its intended method of operation is uncertain.
• Muzzle brake: A distinctive device with ports on the top and sides and a front plate intended to redirect gas and counter recoil. Its design likely increased the muzzle blast.
• Threaded cleaning rod arrangement: The muzzle brake screws onto the barrel and is secured with a split pin. The cleaning rod also uses an unusual threaded arrangement at the nose cap.
• Spring-loaded butt plate: Two internal springs were intended to reduce the felt recoil of the light carbine firing a full-power cartridge.
• Recoil cross-bolt: Present in the carbine but not in the companion long rifle. The trials were testing whether recoil bolts were needed.
• Gas-relief holes: Two holes in the receiver let gas escape upward if a cartridge case ruptures, reducing the risk of gas reaching the shooter.
• Other details: The rifle has a Nagoya Arsenal mark, trial proof marks, a bolt numbered 2 despite the carbine being serial number 4, and a defaced chrysanthemum. It can still accept a standard Type 30 Arisaka bayonet.

Testing and outcome

The rifle and related trial designs were formally tested in October 1938. The rifles were generally considered satisfactory, but the carbines were unpleasant to shoot because of their substantial recoil and muzzle blast. The muzzle brake and spring-loaded butt plate did not sufficiently solve the problem; the brake also aggravated the blast.

The trials led Japan to abandon the cavalry-carbine concept and develop a shorter rifle instead. Japan ultimately adopted the Type 99 in both a long-rifle version and an intermediate-length short-rifle version—not as a carbine. This differed from the approach of many other countries, which adopted an intermediate-length rifle in place of both long rifles and carbines.

Provenance

The carbine was brought home from Luzon in 1945 by U.S. Technical Sergeant Kenneth C. Jager. McCollum shows wartime paperwork authorizing Jager to retain the Japanese carbine and other souvenirs. The rifle’s exact route to Luzon is unknown. Its rubberized-canvas sling is likely a later Japanese addition rather than part of the original trials configuration.

Speakers and sources featured

• Ian McCollum: Presenter and narrator.
• First Lieutenant Palmer: Named in the 1945 document authorizing Jager to retain captured equipment; his written document is quoted.
• Kenneth C. Jager: U.S. Technical Sergeant who brought the carbine home; his retention paperwork is shown.
• U.S. Army Ordnance Report: A 1946 report containing photographs of the companion long rifle, used by McCollum as a comparison source.