Mitrailleuse légère Type 99

The Type 99 light machine gun was a light machine gun used by the Imperial Japanese Army in World War II. It was similar in design to the earlier Type 96 light machine gun, but designed to fire the new and more powerful 7.7 mm Arisaka cartridge, which improved energy by over 50%. Other improvements included the omission of the oiling mechanism which resulted in a better all-round weapon. The Type 99 never fully replaced the previous models of Japanese light machine guns, and served alongside the Type 11 and Type 96 until 1945. Like the Type 96, the Type 99 traces its history to the ZB vz. 26, which also inspired the British Bren light machine gun. Prior to the Type 99's development, the Japanese Army was using the Type 96 light machine gun, an improvement over the previous Type 11 light machine gun. The Type 96 had been introduced into combat service in 1936, and quickly proved to be a versatile weapon to provide covering fire for advancing infantry. Both the earlier Type 11 and current Type 96 light machine guns used the same 6.5x50mmSR Arisaka cartridges as the Type 38 infantry rifle. Using similar ammunition in both guns simplified supply and had the added advantage that any squad member could supply ammunition for the light machine gun, or vice versa. However, in 1939 the Japanese army was in the process of switching to a larger and more powerful 7.7 mm cartridge which also had no rim, which improved cartridge handling. This more powerful cartridge: 3,136 J energy, compared to the earlier 6.5x50mmSR Arisaka cartridge: 1,966 J energy, required a firearm that had more steel, bigger springs and a heavier bolt to handle the extra forces involved. This required a switch from the Type 38 rifle to the Type 99 rifle which could handle the more powerful round. Similarly, it was necessary to develop a new version of the Type 96 light machine gun that would also be able to use this new larger caliber; thus the advantages of common ammunition between riflemen and machine gunners could continue.