Multi-Cannon

Overview

Damage TypeWeapon Type
KineticProjectile
GoodNot Good
Probably the best pure anti-hull weaponKind of meh against shields unless massed fire from several weapons.
Low distributor drawFixed multis are hard to use since you have to constantly adjust aim. 
Does well against modules too. The high damage depends on you actually hitting consistently. 
Gimbaled version does all the fine aiming adjustments for you. 

Size Notes

Most multicannons have to spin up before firing, except the huge version.
Large multicannons require spin-up for several seconds before firing, so it’s important to learn to anticipate and trigger them early so there’s less downtime.
Small and medium multicannons have a much shorter spin up that doesn’t really require anticipation.
Small multicannons are usually used as utility weapons for experimental effects, typically Corrosive Shell.

Powerplay

Enforcers

Small fixed autocannon. 
Has medium level damage and armor piercing in a small package. 
More damage, lower rate of fire, increased range. 
Ammo supply is quite low.
They have the usual difficulty with aiming fixed multicannons, but their high shot speed makes it a bit easier.

Engineering

EfficientNot much point. They’re already efficient weapons. 
High CapacityGood for weapons you use to apply experimental effects.
LightweightFor weight sensitive ships.
Long RangeIncreased shot speed makes it easier to hit, but you’ll be underpowered damage-wise.
OverchargedGreat damage, and the distributor penalty isn’t as bad as it appears.
Rapid FireMany hits per second, but multicannons are already good at that. The reload bonus is nice.
Short RangeThe highest damage option. Multicannons don’t hit well beyond 2 km anyway, and the heat increase is so practically low that it can be basically ignored…unless you’re going with Incendiary.
SturdyNo.

Experimental Effects

Auto LoaderImproves sustained damage by continuously reloading the weapon.
Corrosive ShellOnly works against hulls. Increases damage and improves the armor piercing of ANY weapon striking the hull. Pairs well with High Capacity on a small multicannon.
Double BracedNot that useful. Better to use module reinforcements.
Emissive MunitionsBlocks the effect of low heat/heat sinks. The heat is negligible on a multicannon.
Flow ControlCuts power usage a bit…but this is already a low power weapon.
Incendiary RoundsChanges the damage to 90% incendiary, making it an anti-shield weapon. The heat can get toasty.
Multi-ServosAutoloader works better. 
OversizedAutoloader gives more sustained DPS. 
Smart RoundsIf you enjoy firing into crowds. Or you could aim better. 
Stripped DownRemoves a tiny bit of mass, but there are better places to drop mass than weapons. 
Thermal ShockWorks nearly as well as pulse lasers and beam lasers…except for that reloading pause which allows the target to escape.