A fully-automatic cannon effective against light vehicle armor. Includes support backpack required for reloading.
— Ship Management Terminal
The AC-8 Autocannon also known as Autocannon or AC, is a handheld weapon that fires large caliber armor-piercing, high-explosive shells. It is capable of firing in both semi-automatic and fully automatic modes, with the latter increasing its already substantial recoil. It unlocks at Rank 10.
It is capable of piercing medium armor, with a small AoE explosion when the round impacts. The explosions do not have the same damage radius of the GL-21 Grenade Launcher, but do have the ability to deal heavy damage to enemy weak points. Unlike most Weapons, the AC-8 Autocannon is not reloaded with a single magazine, but from 5-round clips with the associated backpack. Due to this, it is not possible to reload while there are more than 5 rounds in the internal magazine.
The Autocannon has a 10-round internal magazine that is reloaded via 5-round clips pulled from the associated backpack.
Reloading while carrying the backpack causes the Helldiver to drop to one knee and remain immobile during the animation, so be sure to reload only when it's safe to do so.
Reloading a single clip takes 2 seconds, but reloading the entire magazine from empty takes about 5 seconds, due to the Helldiver needing to cycle the bolt in addition to loading the two clips.
The optimal strategy therefore is to never let the magazine run completely empty, as it is for all other magazine fed weapons. As long as there's one round left in the chamber, there's no need to cycle the bolt, saving 2 seconds on reload time.
If the magazine is empty, Helldivers may choose to only load half the magazine and cancel loading the other clip by diving, crouching, switching weapons, or opening stratagem menu. Helldivers are advised to not attempt to cancel the reload by pressing the fire button, as this will discharge the Autocannon, which during reload is pointed at the ground right in front of the wielder. Helldivers will die instantly.
The Autocannon's wielder can carry the ammo backpack, but if a teammate carries that backpack instead, reloading is much faster, facilitating more rounds sent downrange.
Ammo Boxes will add 2 clips to the backpack, and a Resupply box will add 5.
Helldivers are advised to not fire at enemies at point-blank range. The explosion from the Autocannon's explosive rounds will kill the wielder.
It is the only weapon currently in the game that utilizes ammunition clips to feed an internal magazine.
It is a very well-rounded weapon system and highly effective against the Automatons.
It is somewhat difficult to precisely aim if not taking significant time to remain stable, and the explosion area on impact is small. Therefore - while it is effective against tight clusters of small enemies, medium-sized enemies, and weak spots of larger enemies, making it a very flexible choice with long range - its main weakness is dealing with spread-out small targets, like Hunters approaching from multiple directions or a crossfire from Troopers, especially if said enemies should close into melee range.