Nice piece of history you have. Good luck and enjoy.
Though the U.S. Navy and Marine Corps had adopted limited numbers of smokeless powder, bolt-action rifles, the .30-40 was the first cartridge adopted by the US Army that was designed from the outset for smokeless powder. After a brief experiment with a 230-grain bullet loading, the .30 Army loading was standardized in 1894 using a 220-grain metal jacketed round nose bullet with 40 grains of nitrocellulose powder. This loading developed a maximum velocity of 2,000 ft/s (610 m/s) in the 30-inch (760 mm) barrel of the Krag rifle, and 1,960 ft/s (600 m/s) in the 22-inch (560 mm) barrel of the Krag carbine.