I've been flying a blaster Rokh for fun lately and decided that it was pretty cool, but did it out-damage my Rail Rokh when using blasters with Iron ammo? So I decided to do a comparative analysis using Quickfit of the best named and tech II largest rails and largest blasters.
The spreadsheets can be found here.
The skills set is Large Rail Specialization and Large Blaster Specialization both to IV, Caldari Battleship to IV, and the ship in question is equipped with an active Tracking Computer II and three Magnetic Field Stabilizer IIs. I am ignoring factors such as tracking, capacitor usuage, and target transversal speeds or resistances. This is simply a look at raw damages for the extreme ends of the ammo available, Antimatter and Iron, as well as the middle using Lead. Also, I look at the bonus of using Faction ammo, and then the Tech II variants. All calculations are done in Quickfit version 1.3.
My main question, if blasters with Iron out-damage rails with antimatter, was answered with a straight no which wasn't surprising. What was surprising was the margin of difference, over 15 pts per second! With a full rack that is 120+ pts per second difference!
When using the same ammo the blasters obviously had the advantage, but I admit I was mildly surprised to see how much more the blasters increased when using antimatter compared to using lead, almost 30 pts/sec more. When using iron, the difference was only over 10 pts/sec.
The meeting point in my comparisons was rails using antimatter and blasters using lead, or rails using lead and blasters using iron. At those configurations the weapons raw DPS was roughly equal.
The bonus of using Faction ammo was not insignificant. The named 350mm saw a jump of 7 pts/sec, or 56 pts/sec for a full rack of Caldari Navy antimatter. The best named Neutron blaster jumped almost 12 pts/sec. The difference were not as striking at the lower power ammo, but nevertheless were there.
Finally, tech II ammo. The long range Spike ammo in rails gave damage rates comparable to using Lead ammo but at twice the range. The short range Void ammo in blasters gave damage rates 13-15pts/sec more than using antimatter at better range, but half the falloff.
The interesting part for me was looking at the short ranged rail ammo Javelin, and long range blaster ammo, Null. The rails still had the superior range by 5 km for 350mm to Ions and 10km for 425mm to Neutrons, but the blasters still had the superior damage by 10-12 pts/sec. Combined with the superior tracking speed, that is exactly why rail pilots often avoid Javelin ammo.