The name of the 45-70 cartridge originated from the black powder naming convention used in the eighteen hundreds, consisting of the caliber of the cartridge, followed by the load of powder (in grains). The 45-70 cartridge was designed at the United States government-operated Springfield Armory, hence the "government" attachment to the name. The cartridge is defined by a 405 grain, .45 caliber bullet (.458 inch diameter) that is propelled by 70 grains of powder, hence the cartridge received the designation ".45-70-405."