Army Ammunition - Introduction
The following is taken directly from a U.S. Technical Manual on Japanese Explosive Ordnance
Japanese Army weapons are generally copies of German or French designs or are developed following their customs. In comparison with weapons used by other countries in the past few years, the Japanese weapons appear to be outmoded and ineffective.
This is particularly true in considering small arms for if the Japanese ever made any serious attempt to standardize small arms and small arm ammunition there is little evidence of it in the many different calibers and types in use by them. The standard weapon prior to 1930 was 6.5mm, but shortly thereafter this was superseded by 7.7mm weapons. However, this change was never completed and 6.5mm weapons were used extensively in the last war. The foreign influence is apparent particularly after 1939 when aircraft machine guns of German and Italian design were copied.
The earlier aircraft machine guns and aircraft cannon were either modifications of Japanese ground mounts or copies of foreign guns. In more recent years, however, the Japanese designed aircraft cannon as large as 120mm, but nothing larger than 57mm was ever put into service.
Most Japanese artillery weapons were characterized by their immobility as very few of them were designed for rapid motor transport. Although 105mm and 150mm weapons were frequently encountered, the standard field piece was 75mm.
One outstanding characteristic of Japanese Army ammunition is the large variety of types and sizes of mortars which were in use. Mortars were used not only as infantry support weapons but as artillery pieces. They ranged in size from the 50mm Grenade Discharger to the 320mm Spigot Mortar.
The standard Antiaircraft Gun was a 75mm gun but there was also an 88mm Antiaircraft Gun which was one of their most effective artillery pieces and a 105mm AA gun. The Japanese had designed a 150mm Antiaircraft Gun for the defense of the home islands but this was used only in the last few months of the war.
The newest trend in research and development in ammunition was along the line of rockets. Very few types of Japanese rockets were used during the war but there were many experimental models of antitank and artillery rockets in development, ranging in size from 75mm to 60cm.
Research was also being conducted on smoothbore and recoilles waepons but this was a relatively new program and none of these weapons was ever developed beyond the experimental stage.
Next Time: Imperial Japanese Small Arms Munitions