Burst Fire
A firing mode in which the gun will fire a certain number of rounds, a burst, per one trigger pull. This is full-automatic fire at full cyclic speed but the burst size is limited, usually to three rounds. This option is used in some firearms (e.g. M16A2, certain MP5 models) because there is evidence that, in real firearms with recoil, the accuracy drops significantly after the third round of full automatic fire. Some airsoft guns duplicate this feature which is very cool if not all that useful.