The M1947 Johnson auto carbine was intended as a replacement for a .30 caliber semi-automatic rifle that was standard US service rifle during World War II, the Korean War, and a limited amount when?
M1 Garand The M1 Garand is a .30 caliber semi-automatic rifle that was the standard U.S. service rifle during World War II and the Korean War and also saw limited service during the Vietnam War. Most M1 rifles were issued to U.S. forces, though many hundreds of thousands were also provided as foreign aid to American allies. The Garand is still used by drill teams and military honor guards. It is also widely used by civilians for hunting, target shooting, and as a military collectible.
.30-40 Krag The .30-40 Krag (also called .30 U.S., or .30 Army) was a cartridge developed in the early 1890s to provide the U.S. armed forces with a smokeless powder cartridge suited for use with modern small-bore repeating rifles to be selected in the 1892 small arm trials. Since the cartridge it was replacing was the .45-70 Government, the round was considered "small-bore" at the time. The design selected was ultimately the Krag–Jørgensen, formally adopted as the M1892 Springfield. It was also used in M1893 and later Gatling guns.