The Multi-cannon is a small calibre machine gun that rapidly fires kinetic projectiles. Multi-cannons consume less power than energy weapons, generate less heat, and have a longer range, but have a finite stockpile of ammunition that must be replenished.
Multi-Cannons, or MCs, are available as fixed, gimballed or turreted weapons. They fire in a continuous hail, are relatively easy to keep on target and have a low distributor draw meaning you can group them with other more energy-hungry weapons such as lasers.
As a Kinetic weapon they deal less damage to shields and more to hulls. They also have a fairly long range with damage only dropping off past 2000m, and maximum range at 4000m, meaning they are useful for chasing down enemies who are trying to escape your range to recharge shields.
However they require continuous fire, are subject to a spin-up time and damage may be deemed gradual by some. The notable exception is the Class 4 MC which fires higher-calibre shells at a slower rate and has a better armour-piercing capability with NO spin-up delay.
They are available for class 1-4 hardpoints.
As with many weapons, Overcharge is generally deemed to be the best configuration. Corrosive effect does not stack, so put it on your smallest MC. For larger MCs, there are myriad playstyles, but Incendiary Rounds are popular, and having Emissive Munitions on a small MC will be useful against players employing Silent Running. If in doubt, Oversized is a good starting point to improve your DPS while on-target.