The autocannon is the Imperium’s go-to rapid-firing heavy gun: a big-calibre, hard-hitting weapon that sits somewhere between a heavy machine gun and a tank cannon. It shows up on everything from Guard tripods to Space Marine warsuits, and it’s one of the most common answers to infantry hordes and light armour.
What the autocannon actually is
Think of it as a 20th-century tank gun that kept evolving. The autocannon is a rapid-firing weapon with a large calibre, usually mounted on a carriage or a vehicle because it’s simply too heavy to carry.
Calibres vary wildly by pattern, running from around 25mm or 30mm up to 50mm, 55mm, and in some cases a massive 105mm. It can fire a wide range of ammunition, from mass-reactive explosive shells to solid rounds and armour-piercing sabot used by the Space Marines.
Why it matters on the battlefield
The autocannon’s selling point is its combination of rate of fire and killing power. That makes it excellent against large infantry formations and light armoured vehicles.
It’s also a natural counter to big Tyranid organisms and Ork vehicles, since it can put out enough shots to matter against tough, mobile targets. Against heavy infantry like Space Marines it still works, though power armour has been known to stop autocannon rounds.
- Great against: massed infantry, light vehicles, large Tyranid creatures, Ork vehicles.
- Usable against: heavy infantry, though Marine power armour can shrug off hits.
- Common mounts: tripods, weapon carriages, tanks, walkers, and warsuits.
Who fields it
The autocannon is everywhere in Imperial service. The Imperial Guard, Space Marines, Witch Hunters, and Chaos Space Marines all use it, along with planetary militias and traitor armies.
Orks are especially fond of it, and more than for the damage. They love the noise and the recoil it produces when fired.
Notable patterns
There’s no single autocannon, there’s a whole family of patterns. Some are vehicle-mounted, some are towed, and some are built into specific chassis.
A few names come up again and again in the lore, from the Predator’s Syrtis pattern to the Accelerator autocannon carried by Space Marine Suppressors.
| Pattern | Notable use |
|---|---|
| Syrtis pattern | Predator Destructor (the Predator autocannon) |
| Accelerator autocannon | Space Marine Suppressor squads |
| Ironhail pattern | Invictor Tactical Warsuits |
| M34 autocannon | Imperial Guard in the Calixis sector, tripod-mounted |
| Mk IX Chass Fabrik | Tanith First & Only company support |
| Magna-Coil autocannon | Leagues of Votann Magna-Coil bikes |
Key facts
- The autocannon is a rapid-firing, large-calibre weapon, usually vehicle- or carriage-mounted.
- Calibres range from roughly 25mm up to 105mm depending on the pattern.
- It’s effective against massed infantry and light armour, and useful against heavy infantry.
- Users include the Imperial Guard, Space Marines, Chaos Space Marines, militias, and Orks.
- Common patterns include the Syrtis, Accelerator, Ironhail, M34, and Mk IX Chass Fabrik.
FAQ
Is the autocannon good against Space Marines?
It can hurt them, but it’s not a hard counter. Marine power armour has been known to stop autocannon rounds, so it’s better against lighter targets.
What’s the difference between an autocannon and a lascannon?
The autocannon trades raw armour penetration for a much higher rate of fire and a wider range of ammunition. The lascannon is a slower, single-shot anti-tank weapon.
Can a single person fire an autocannon?
Some patterns are designed for a two-person crew, but a lone gunner can operate one if they have to. Most are mounted because of the weight.