Rate of Fire

The rate of fire (also firing rate, fire rate, RoF) of a firearm is the number of rounds that it can cycle in a given period of time. This is usually measured in rounds per minute (RPM). Modern automatic firearms can approach 1000 RPM, while certain weapon systems have attained rates as high as one million RPM.

Selective fire
Many modern firearms offer a switch to select between different fire settings. In game, this is done either by re-selecting the weapon (with the key), or with a dedicated  key.

Semi-automatic
A semi-automatic weapon will fire only one round per trigger pull, while also cycling the next round (unlike a bolt-action weapon). Recoil and distortion due to weapon heating tend to throw off the accuracy of further rounds in other firing modes—using the semi-automatic mode allows a shooter to place accurate fire at a distance.

A shooter at long range can often place more shots on target with semi-auto fire than with even a controlled automatic spray.

Burst fire
In this mode, one trigger pull will cycle two or three shots. The weapons that use this mode tend to have lower recoil, allowing a shooter to place a relatively tight grouping with little effort. Certain other weapons are designed to enforce conservation of ammunition or better marksmanship discipline, such as the M16A4 and KH2002 (although the real-world weapon does offer automatic mode).

The Beretta M93R is a notable burst-fire pistol.

Automatic
Automatic or full-auto mode allows the shooter to fire continuously while the trigger is depressed. Machine guns are designed with this feature in mind, along with many assault rifles and PDWs. The Glock G18 is an automatic pistol.

Automatic fire is often less accurate than other firing modes. The shooter may need to adjust their aim as recoil accumulates and the weapon drifts off-target.

By depressing a trigger for a short time, a shooter can burst fire an automatic weapon. This may be necessary when the game allows for the weapon to overheat, or to preserve accuracy at long range.