Rate of fire
Rate of fire is the frequency at which a specific weapon can fire or launch its projectiles. It is usually measured in rounds per minute (RPM or round/min), or rounds per second (RPS or round/s).
Several different measurements are used. The fastest and most commonly quoted rate is the cyclical rate of fire. However, heat (possibly leading to weapon failure) and exhaustion of ammunition mean most automatic weapons are unlikely to sustain their cyclic rate of fire for a full minute. That is why lower rates apply in practice and it is incorrect to describe RPM as "the number of rounds a weapon can fire in one minute."
Overview
For manually operated weapons such as bolt-action rifles or artillery pieces, the rate of fire is governed primarily by the training of the operator or crew, within some mechanical limitations. Rate of fire may also be affected by ergonomic factors. For rifles, ease-of-use features such as the design of the bolt or magazine release can affect the rate of fire.