The Autocannon is one of the most common ballistic weapons seen on the battlefields. From stationary emplacements to tanks to BattleMechs, the Autocannon is a tried-and-true design, though with more than its share of problems.
Autocannons fire conventional propellant-cased shells of varying sizes. These range from High-explosive Armour-piercing rounds to fragmenting cluster shots. Autocannons have among the widest range of calibers relative to other weapon types From the paltry 25mm cannon to the deafening 200mm cannon, Autocannons can be found fit and capable for any and all ranges and tactical requirements.
Autocannons are classed by their capacity to inflict damage. Class /2 Autocannons inflicting the least damage per salvo, with Class /20 Autocannons dealing the most devastating of barrages. A Class /5 Autocannon ranges from solid-shot 85mm cannons to 50mm repeating cannons, but both are classed for their damage output, rather than simply the bore of the gun.
The lightest Autocannons are the Class /2. Commonly fitted to Battlemechs expected to strike at aerospace fighters and VTOL air support craft, this Autocannon has limited use against other Battlemechs.
The Blackjack is well known for mounting two Class /2 Autocannons to provide solid fire support and to score entire wings of aerospace fighters.
The Class /5 Autocannon, often referred to as the "Tactical Autocannon" is a staple of the Autocannons. Capable of culling aircraft and ground vehicles alike, it also provides a respectable punch to engage 'Mechs from a variety of ranges. Though its weight restricts many LightMechs from mounting one, it is a reliable tool among the Medium lass of 'Mechs.
The Shadowhawk is a reliable and respected 'Mech well known for apt use of the Class /5.
The Class /10 Autocannon is the go-to design for those that want a strong, heavy-handed right hook. Capable of stripping a ton and a half of armour per salvo, the /10 can easily threaten 'Mechs of all weight classes. Though it lacks the range of the lighter cannons, and in fact weighs enough of its own to prohibit heavy use of it, none can deny its effectiveness in combat.
The Centurion and Enforcer both mount Class /10 Autocannons and use them with brutal efficiency, showing that pure tonnage isn't everything.
The Class /20 Autocannon stands among the largest and most imposing weapon any soldier - Mechwarrior or otherwise - may bring to the field. Capable of obliterating over two tons of armour in just one shot, this cannon is only seen on the heaviest of 'Mechs capable of off-setting its oppressive logistics demands. Infamous for its brutality, it is recognized in and made famous 'Mechs such as the Hunchback and Atlas.
The Autocannon, while a strong weapon system, is not without its flaws. Compare to more advanced energy-based weapons, such as the Large Laser, the Autocannon is a tad lackluster in damage output for the sheer tonnage demands. Often times being two to ten times as heavy as other weapons, many 'Mechs pass over these guns solely because they can't physically carry the weight.
Ammunition demands become more strict as one increases the size of the gun, with ammunition bins carrying fewer shots per ton. Prone to cooking off in heat-intense situations or when struck by direct fire, they can be as dangerous to the pilot as they are to the enemy.
Still, Autocannons have advantages of their own. Compared to Lasers, Autocannons are very heat-efficient for their damage output, and ballistic-heavy payloads can often remain cool to the touch long after other 'Mechs have be forced to withdraw to avoid cooking themselves alive.
This is especially valuable in hostile environments, such as arid or martian worlds, where managing heat may make or break an engagement.