as well as the German Gewehr 43, were semi-automatic gas-operated rifles issued during World War II in relatively small numbers. In practice, they did not replace the bolt-action rifle as a standard infantry weapon of their respective nations - Germany produced 402,000 Gewehr 43 rifles, and over 14,000,000 of the Kar98k. Another gas-operated semi-automatic rifle developed toward the end of World War II was the SKS. Designed by Sergei Gavrilovich Simonov in 1945, it came equipped with a bayonet and could be loaded with ten rounds, using a stripper clip. It was the first widely issued rifle to use the 7.62×39mm cartridge, and the SKS, along with its Chinese copy, the Type 56, is one of the most popular semi-automatic rifles. By the end of World War II, however, semi-automatic rifles had been largely superseded in military usage by their fully automatic counterparts - weapons such as the AK-47, FN FAL and M16 limited the viability of widespread deployment of semi-automatic rifles. Gradually, military doctrine placed less emphasis on individual marksmanship, as a large volume of fire was deemed more important - during World War II, American ground forces fired approximately 25,000 rounds for each enemy killed. In the Korean War, this was raised to 50,000, and in the Vietnam War it was 200,000. The first fully automatic rifle to see widespread usage was the German StG 44, which was well liked by troops, as the 30-round, selective fire rifle gave them much more flexibility than their service rifle, the bolt action Karabiner 98k. Ultimately, automatic rifles would become standard in military usage, as their firepower was superior to that of a semi-automatic rifle, but both semi-automatics and even bolt actions are still used worldwide in military service in specific roles, such as designated marksman rifles where the greater accuracy compared to automatics is valued. Furthermore, to accommodate for this greater firepower, battle rifles were mostly replaced by assault rifles, whose lighter bullets allowed more to be carried at once, but where semi-automatic rifles continue to be used, they are usually in higher calibers, such as the .50 BMG Barrett M82. Operation Semi-automatic weapons use gas, blow-forward, blowback or recoil energy to eject the spent cartridge after the round has moved down the barrel, chambering a new cartridge from its magazine, and resetting the action. This enables another round to be fired once the trigger is depressed again. Semi-automatic rifles