Prior to the Type 99's development, the Japanese Army was using the Type 96 light machine gun, a successor to 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 Type 11 and Type 96 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 7.7mm cartridge which also had no rim, which improved 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. The Type 99 light machine gun was produced at Kokura,
Nagoya Arsenal and
Mukden with a total production of about 53,000 weapons. ==Design==