Dreadnought features a lot of different beam and projectile weapons as main guns.
The so-called "primary" weapons are bound to the specific ship and cannot be changed. Also, the primary weapon type stays the same on all ships of a given class and manufacturer no matter which tier the ship is.
Damage of course scales with tier and some characteristics may change as well. Be prepared for varying behavior, when progressing through tiers as projectile speed and even range interval boundaries can have their values changed in any direction.
But the basic handling of a primary weapon usually remains what it is. So, you don't have to re-learn its usage, when reaching the next tier.
As a secondary weapon you usually have a choice of two different options.
On most ships the secondary weapons are meant for a different purpose than the primaries. Most of the time you will find the secondaries to have other range or firing arc characteristics.
Many secondary weapons have a smaller clip size, so you will have to reload more often.
You can switch between primary and secondary weapons by pressing [Q].
While "beam" really means a constant continuous beam "connecting" the weapon with your target, projectile covers everything else - even blaster-like guns.
The projectile weapons differ considerably in projectile speed. That is not only the case because of various technologies (plasma bolts, blasters, ballistic cannons, etc.). Projectile speed also varies depending on the weapon model (light, heavy, dual, ...).
As a rule of thumb, you usually can expect energy projectiles to travel faster than bullets. Making them somewhat easier to aim with.
Range and Damage
All weapons are implemented with three range intervals. Sometimes two intervals have the same characteristics and thus weapon tooltips may show only two or even only one interval.
While weapon damage of course decreases with increasing distance, damage is not scaled like in GSF. The interval boundaries are hard switch points.
So, it's very important to know the interval boundaries!
The mouse icon shows the range interval your target is in:
Yellow - long range
Orange - medium range
Red - close range
Orange - medium range
Red - close range
You can use "Power to Weapons" (PtW, [F3] if not re-bound to [F1]) in Dreadnought to amplify the damage of your primary and secondary weapons. Note: module damage is not increased by PtW.
PtW boosts raw damage as well as the rate of fire.
Most of the time you can expect to have 50% more DPS with PtW.
The exact percentage differs between the weapons and there are some exceptional values. For example, the Oberon destroyer guns almost double their DPS, while most corvettes seem to be at 35% (though already having an insane base DPS).
Be sure to not completely drain your energy by using PtW if it is not completely safe to do so. Energy management is crucial in Dreadnought and you will most likely want to keep some energy for shielding to retreating.
(Use [F4] to stop energy usage.)
Most weapons have 360° firing arc. Artillery cruisers usually have their primary weapon more or less fixed to the direction the ship points to. This is also true for the Jupiter Arms and Akula Vektor corvettes.
Though having a 360° weapon doesn't mean you can really fire everywhere. The angles for firing above and below are usually limited to about 60°.
If a target is outside of your firing arc you can see this by a pointed tracking line showing the distance between your mouse position and the nearest point your weapon could hit.
You can zoom in on your target, allowing for easier aiming.
Press and hold the right mouse button to zoom.
All projectile weapons have to reload after having fired a certain number of shots (see "clip size" in tooltips).
Reloading is triggered automatically if the clip is empty. Reload times vary by gun and usually interrupt your attack in a noticeable way.
If you are not firing you should always make sure you have fully loaded guns (press [R] for reload).
Watch the yellow bars showing your ammunition. The left-hand side shows primaries, the right-hand side secondaries.