Autocannon

The autocannon is a rugged, large-calibre automatic gun that fills the gap between the bolter and the battle cannon. It hurls streams of high-velocity solid shells (kinetic slugs and small explosive rounds) that chew through infantry, light vehicles and low-flying aircraft with equal ease. Its heavy, rhythmic pounding is one of the signature sounds of an Imperial firefight.

Unlike energy weapons, the autocannon needs no volatile fuel cells or fickle machine-spirits; it demands only shells and a mount strong enough to soak its considerable recoil. This makes it endlessly reliable and beloved of quartermasters, for its ammunition can be forged on any world with a foundry and stockpiled without fear of it spoiling or discharging on its own.

It arms the weapon teams and Sentinel walkers of the Astra Militarum, the heavy squads of the Space Marines, and the turrets of a thousand patterns of tank and gun-carriage. Versatile and unfussy, able to threaten almost anything short of a main battle tank, the autocannon will still be hammering out shells long after more exotic weapons have jammed, overheated or run dry. It is not a glamorous gun, but it is one the Imperium can never have enough of. Crews come to trust it as they trust few other weapons, knowing that when the energy guns have burned out and the rare munitions are spent, it will still be there, pounding out its shells as steadily as a beating heart.