A selective fire firearm has at least one semi–automatic and one automatic mode, which is activated by means of a selector which varies depending on the weapon's design. Some selective fire weapons utilize burst fire mechanisms to limit the maximum number of shots fired automatically in this mode. The most common limits are two or three rounds per trigger pull. Fully automatic fire refers to the ability for a rifle to fire continuously until the magazine is empty. "Burst-capable" fire refers to the ability of a rifle to fire a small yet fixed multiple number of rounds with one trigger pull. Semi-automatic refers to the ability to fire one round per trigger pull. The presence of selective fire modes on assault rifles permits more efficient use of rounds to be fired for specific needs, versu