Rotary guns

Related:
* Multi-barrel guns - non-rotary multi-barrel guns

Usually games include a spin up and spin down delays and possibly secondary button to spin up the gun without firing (or allows pressing the firing button momentarily and "pulsing" that to keep the spin up without firing while teetering on the edge of sufficient spin).

Most commonly seen mounted on gunships (e.g. attack helicopters), though sometimes used for missile defenses (e.g. Phalanx CIWS).

Notes:
* Early designs of rotary guns were operated by a hand crank and probaly couldn't reach anywhere near the firing rate of modern machine guns, not to mention the modern rotary guns that are capable of expelling 6000 or more bullets per minute (100 per second).
* Modern rotary guns actually make more of a whining sound than the old rat-tat-tat of machine guns (caused by the spinning and the ridiculous amount of bullets expelled that you can't possibly distinguish from each other).
* The purpose of the rotating barrel setup is for cooling, thus firing rate should be at least multiplied by the number of barrels compared to single barrel setups if not more (each additional barrel gives all the others one shot more time to deal with heat), not to mention the spinning gives the barrels better airflow around them and thus even better cooling.