For a third hybrid class of weapons, common in handguns and rifles, known as a semi-automatic firearm, the rate of fire is primarily governed by the ability of the operator to actively pull the trigger. No other factors significantly contribute to the rate of fire. Generally, a semi-automatic firearm automatically chambers a round using blowback energy, but does not fire the new round until the trigger is released to a reset point and actively pulled again. Semi-automatics' rate of fire is significantly different from and should not be confused with full-automatics' rate of fire. Many full-automatic small arms have a selective fire feature that 'downgrades' them to semi-automatic mode by changing a switch.