The 6.5 x 50mm cartridge was introduced in 1897 and served as a Japanese military cartridge through World War II. Both the Model 1905 and its successor, the Model 99 Arisaka rifles, were chambered for this cartridge. The 6.5 x 50mm military cartridge was loaded with a 139 grain bullet at 2500 fps in a 32" barrel. No one has ever accused the Arisaka rifle of being handsome, but as several authorities like P.O. Ackley were eventually discovered, it was probably the strongest and safest bolt action battle rifle ever built. When subjected to destructive testing, loads that blew apart '17 Enfield, '03 Springfield, and '98 Mauser actions were taken in stride by the Arisaka action. Norma6.5 x 50mm ammunition and unprimed cases are still available. Any of the .264" bullets will work in this cartridge, but due to its relatively small powder capacity, those weighing 120, 125, and 129 grains are best for deer. The small powder capacity also calls for powders of medium burning rate with H380, H335, and H4895 doing a good job. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.