Semi-automatic rifle

A semi-automatic rifle is a self-loading rifle that fires a single round each time the trigger is pulled. In contrast, a fully automatic rifle continuously fires rounds as long as the trigger is pressed and there is ammunition left.

Semi-automatic weapons use gas, blowforward, blowback, or recoil energy to eject the spent cartridge after the round has traveled down the barrel, chambers a new cartridge from its magazine, and resets the action; enabling another round to be fired once the trigger is depressed again.

The self-loading design was a successor to earlier rifles that required manual-cycling of the weapon after each shot, such as the bolt-action rifle or repeating rifles, which required the operator to manual cycle the action before each shot. The ability to automatically load the next round allowed for an increase in the rounds per minute the operator could fire.

These rifles are also known as self-loading rifles ('SLR') or auto-loading rifles and are often mistaken for automatic rifles or machine guns. Self-loading rifles were one of the most revolutionary designs in the history of warfare. To name one example, semi-automatic weapons gave the United States an important edge in World War II, as the M1 Garand was a semi-automatic rifle issued to most soldiers, whereas the Axis powers had only bolt action weapons and limited quantities of semi-automatic rifles. Semi-automatic rifles are versatile designs. They can be efficiently fed by en-bloc clip and internal magazine, detachable magazine or a combination of stripper clip and internal magazine.

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