Autocannon turret

The autocannon turret is a defense structure that fires a burst of medium-damage shells.

Acquisition

Autocannon turrets can be constructed once the Autocannon turret research project has been completed. They require 350 Steel, 40 Plasteel, 6 Components, 15,000 ticks (4.17 mins) of work, and a Construction skill of 6.

Summary

The autocannon turret uses the autocannon weapon. In addition to the weapon's accuracy, the turret itself has a per-tile shooting accuracy of 96% or equivalent to a Shooting skill of 8. It has a maximum range of 32.9 tiles, but is unable to hit enemies within an 8.9 tile radius. These ranges are centered on the lower left tile of the turret, regardless of orientation. Despite its damage, the autocannon's stopping power is almost non-existent, not even being able to stagger humans - the same is also true for the uranium slug turret.

After firing 90 rounds, it needs to be reloaded with 180 steel by a hauler. This can be adjusted in the storyteller settings, but all default difficulty settings do not alter this.

Since autocannons are large 2x2 structures, ranged attacks are twice as accurate against them. And as of version 1.3.3117, turrets don't benefit from cover. Despite displaying in the mouse-over box as such, empirical testing demonstrates that turrets do not benefit at all.^[1]

Like all turrets, they cannot target enemies through blind smoke and are temporarily disabled by sources of EMP, with downtime scaling to the EMP damage dealt. Unlike mechanoids, turrets do not adapt to EMP and thus can be continuously restunned.

Visualization of effective turret range of all three turrets, from uranium slug turret (top), to autocannon turret (middle), to mini-turret (bottom).
Green is 80 - 100% of peak accuracy, blue is 50 - 80% of peak accuracy, red is below 50% of peak accuracy and grey is outside range. Gold tiles are spaced every 5 tiles. Values from 1.0.

Explosion

Autocannon turrets have a 50% chance to explode when damaged below 20% health. The exploding turret will spark and emit a hissing sound for 240 ticks (4 secs) before exploding, dealing 50 Bomb damage in a 5.9 tile radius centered around the lower left tile of the turret. Bomb damage is multiplied 8x against walls, 4x against other impassable structures and plants, and 2x against passable buildings. All nearby raiders will attempt to move out of the blast radius before detonation.

Radius of autocannon turret explosion. Note the slight offset from the 'true' center of the turret.

Analysis

In general, turrets are not very strong for their price. Outside of the easier difficulties, you shouldn't expect turrets to defeat raids on their own. They are best used when massed up, to support colonists, rather than replace colonists.

Autocannons are a general purpose turret. They can be useful in killboxes, where turrets can be massed together. However, they are quite costly. In an open field, the autocannon's low accuracy makes it less viable.

If you want automated firepower, autocannon turrets are usually your best bet. Other turrets have their niches beyond firepower, however:

Mini-turrets offer less firepower at most ranges. 4 mini-turrets offer less DPS than 1 autocannon, past 12 tiles of range. The advantage of mini-turrets is that they are effective distractions. They are cheap, meaning they are great for taking fire from enemies.
Uranium slug turrets are not strict upgrades. The autocannon actually outdamages the uranium slug turret until 25 tiles of range (before AP). Even then, since the uranium slug turret has a tendency to overkill, they are almost always worse against human targets. The uranium slug turret's advantages are the massive range and massive AP. They are effective against centipedes and other heavy targets.

Graphs

True DPS over Range

Version history

0.19.2009 - Added.
1.1 - Its damage and armor penetration was halved (40 -> 20, 60% -> 30%), and the reload cost was increased (120 -> 180 baseline).
1.1.2618 - Damage and armor penetration was increased (20 -> 25, 30% -> 37.5%).
1.3.3200 - Damage increased from 25 to 27. Accuracy increased: touch 0.25 -> 0.28, short 0.65 -> 0.72, medium 0.6 -> 0.66, long 0.45 -> 0.5. Turret ammo cost is no longer factored by difficulty.

Architect