"Thunderhead" Heavy Autocannon

Purchased for:

 — Item Description

The **"Thunderhead" Heavy Autocannon** is an unlockable primary weapon for the Gunner. It is an oversized heavy machine gun with two massive barrels extending outwards which fire in sequence. The weapon is loaded by a huge double ammo drum.

The Heavy Autocannon fires explosive rounds which detonate upon hitting the world or a target. Enemies hit directly by rounds take both the damage of the bullet and the explosive damage at once. The rounds fired start out with a sluggish fire rate, but this can build up over time the longer the trigger is held.

## Modifications

There are five tiers of modifications and each tier has two to three upgrades. Only one modification can be equipped per tier.

## Overclocks

Overclock calculations happen after modifiers.

## Stats Breakdown

### Understanding the Weapon

* **Damage** is how much damage is dealt upon direct impact of the shot.
* **Area Damage** is how much damage is dealt in addition to the direct damage within the damage radius around the impact.
* **Top Rate of Fire** is the max rate of how quickly shots can be fired after sustained firing.

#### Rate of Fire Mechanics

* The Autocannon has two hidden stats regarding rate of fire, which is its **Starting Rate of Fire** and **Rate of Fire Scaling**. They play an important role in determining how quickly max rate of fire bonuses are applied, and can be changed depending on which modifications/overclocks are taken.
* **Starting Rate of Fire** default is **3.4**
	+ This determines how quickly shots are initially fired as its rate of fire starts to ramp up.
* **Rate of Fire Scaling** default is **0.4**
	+ This is the coefficient of the exponential function that is used during the rate of fire rampup. The Autocannon's initial rate of fire continues to be scaled until the top rate of fire has been reached, which would then allow max rate of fire bonuses to be applied.

* **Modifications/Overclocks that affect Rate of Fire:**
	+ **Improved Gas System**
		- +0.3 Starting Rate of Fire
		- +2 Top Rate of Fire
	+ **Lighter Barrel Assembly**
		- +0.6 Starting Rate of Fire
		- x1.5 Rate of Fire Scaling
	+ **Supercharged Feed Mechanism**
		- +0.3 Starting Rate of Fire
		- +2.0 Top Rate of Fire
	+ **Big Bertha**
		- -1.5 Top Rate of Fire
	+ **Combat Mobility**
		- x1.5 Rate of Fire Scaling
		- +0.9 Starting Rate of Fire
* **Rate of Fire Formula**
	+ Let **S** be the Starting Rate of Fire
	+ Let **C** be the Rate of Fire Scaling
	+ Let **M** be the Max Rate of Fire
	+ Let **t** represent the amount of seconds that has elapsed since the Fire button has been held down.
	+ The Rate of Fire at any given time, t, can be represented as such:
		- \[R(t) = \min(S\*e^{Ct}, M)\]
	+ Such that when enough time has elapsed and \[S \* e ^{Ct} \ge M\], time is no longer a factor in the Rate of Fire. At this point, the "Max Rate of Fire" Bonuses should kick in.

### Unique Overclocks

#### Neurotoxin Payload

**Neurotoxin Payload** is an Unstable Overclock. It grants all shots a 50% chance to inflict Neurotoxin onto an enemy. When an enemy is affected by Neurotoxin, they will take 12 Poison damage every 0.75 - 1.25 seconds for 10 seconds, as well as having their movement speed reduced by x0.3. Hitting an enemy who is already affected by Neurotoxin with another round which inflicts the debuff will reset its timer.

## Mastery

Each modification that is purchased advances a mastery bar by one unit.

Mastery unlocks:

* Three modifications – **First Stripe** Weapon Paintjob
* Seven modifications – **Deepcore** Weapon Paintjob
* All (14) modifications – **The Company Special** Weapon Paintjob

## Skins

Full gallery of skins can be seen at Weapon Skins.

## Trivia

* The weapon's full ammo interaction consists of the Gunner taking out one of its bullets and balancing it by the tip on his hand for a moment before returning it to his pocket.

* Mission Control's dialogue upon completing the Weapon License Assignment for the Autocannon reads as follows:
	+ "*Good work. Management believes you're ready to handle our Heavy Autocannon, the "Thunderhead"... Be mindful not to blow off your own legs with it. This thing has a proper kick to it."*
* In older versions of the game the Powered Minigun also fed from a large ammo drum which needed to be reloaded, on top of its overheating issues. This was changed in Update 11: Dead and Gun to the current system where the Minigun feeds from a single drum and does not reload. It is likely that the Minigun's older reloading system influenced the Autocannon's design when it was added to the game a few months later in Update 19: Guns! Lots of Guns!

* Before Season 01: Rival Incursion, the Autocannon was incapable of dealing friendly fire to teammates.
* The minimum caliber for an autocannon is normally considered to be 20mm. The Thunderhead's description states it shoots .50 cal, and as such the Thunderhead is either a heavy machinegun or shoots actual 20mm rounds (which would normally induce a devastating recoil). It is possible the thunderhead fires 20 mm or above and uses sub calibre rounds like apcr.

 This page is possibly not up to date.

 This page is possibly not up to date. It was last updated for Update 34: Modest Expectations