58mm

The 7.7×58mm Arisaka cartridge, Type 99 rimless 7.7 mm or 7.7mm Japanese was a rifle cartridge which was used in the Imperial Japanese Army's Arisaka Type 99 rifle and machine guns, and was the standard light cartridge for the Imperial Japanese Army Air Service, such as the Type 89. The Imperial Japanese Navy (and Imperial Japanese Navy Air Service) never shared weapons or ammunition with the army, instead adopting the 7.7x56mmR, a direct copy of the .303 British round. The cartridge was designed to replace the aging 6.5×50mm Arisaka after seeing the effectiveness of the MG 34 GPMG in action (firing 8×57mm IS full power military rifle ammunition) in China during 1937. Due to a lack of materials, the plan to phase out the 6.5 mm Arisaka cartridge by the end of the war was not completed.

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