Rail Guns

Overview

Damage TypeWeapon Type
2/3rds Thermal, 1/3rd KineticHitscan
GoodNot Good
High burst damage at range or up close. Firing repeatedly will toast your ship.
Canceling SCBs with Feedback Cascade. Ammo runs low quick unless you take a particular experimental.
CMDRs with good aim who like to destroy modules.The damage mix means you’re not doing as much damage to shields or hull as you think due to resistances. 
Armor Penetration is 100, so you always do full damage.The firing delay when triggered and the need to release trigger to fire again. 
There are only 3 experimentals that lower heat, so you basically have to pick one of those. 

Size Notes

The two different sizes have different firing rates.

Powerplay

Imperial Hammer

3 shot automatic rail gun. 
Damage of 3 shots is slightly more than 1 shot of a regular rail. 
Very high heat, higher distributor draw. 
Unlike rails, fires continuously when trigger is held. 
You need to hit with all 3 shots to get comparable Feedback Cascade performance. 
As with other similar weapons, they’re less effective for module damage due to the need for 3 breach rolls to do the damage of 1 roll of the single shot version.

Engineering

High CapacityBigger clip, but the damage over time is only slightly higher due to fewer reload pauses. 
Lightweight A good choice on smaller ships if you want to punch above your weight class.
Long RangeGood burst with no falloff, and since they’re fixed weapons you can hit all the way out to 6 km.
Short RangeVery good burst at point blank range, but you’ll have to do something about the heat.
SturdyNo. Actually not a bad idea if you want to cancel most of the heat.

Experimental Effects

Double BracedUse a module reinforcement instead. 
Feedback CascadeIf an enemy ship is using a SCB and you can hit with this during the spin-up, you will “cancel” part of the shield reinforcement. It does cost you 20% of your damage. Lowers heat.
Flow ControlFrees up a tiny bit of power, but there are better ways to do that.
Multi-ServosFiring faster is not always better, especially with this weapon’s heat. 
OversizedThere are better ways to do more damage with rails.
Plasma SlugDecreases damage by 10%, but you draw ammunition from your fuel supply. Depending on the ship (and its fuel tank) that can extend your fighting time by a lot. Lowers heat.
Stripped DownFrees up a tiny bit of mass, but there are better ways to do that.
Super PenetratorSlows your firing rate a bit, but you do damage to any module hit in a straight line on hull impact. Lowers heat.