Japanese Type 99 Arisaka Rifle
The Type 99 rifle was introduced in 1939, where it was intended to replace the older Type 38 rifle. During the Second Sino-Japanese war it was discovered that the Type 38's 6.5mm cartridge had become obsolete and that an updated round would be necessary. The Type 99 fired an updated 7.7mm round but the Japanese were never able to fully convert over to the newer rifle and many Type 38s remained in use until the end of the war.