Naval coilgun

A naval coilgun is a type of magnetic weapon system that is most widely used by the UNSC Navy.

Description
Naval coilguns are a large, diverse group of armaments, ranging from relatively light dual-purpose cannons, to station-mounted superweapons measuring kilometers in length. All are designed for use against enemy warships, accelerating their shells through the use of dense electromagnetic coils that run the length of their barrels. Their shells are usually heavy slugs made out of tungsten or depleted uranium, and deal damage by concentrating kinetic energy within as small an area as possible. Weight and size constraints of the shell prevents naval coilguns from having the same range and guiding qualities of missiles, so outside of spinal cannons and battleship batteries, they are limited to short and medium ranges. To make up for this, their higher initial velocities and more solidly-built munitions means that regular countermeasures used for deterring missiles do not work on these weapons. Because of power constraints, most models fire in at a slow, steady pace.

Because of their size and expense, naval coilguns can be mixed-and-matched with various turret mounts, with most being twin arrangements. These turrets are generally unmanned, and are instead coordinated via a sophisticated targeting computer that received orders from the battery commander or fire control officer on the bridge. A manual control station may be included on some ships as a backup.

Naval coilguns can utilize a wide range of shells, although kinetic kill vehicles and semi-guided shells are the most common.

Naval autocannon
A somewhat more specialized category, naval autocannons distinguish themselves from other coilguns by their much faster rate-of-fire. This is usually accomplished by using a combination of smaller shells, alternating coilguns, and a substantial electrical storage bank. They are generally used as part of a ship's tertiary battery, where most act as a deterrent against both fighters and swift attack vessels. Although they can fire at a steady rate, they usually fire in blitzing salvos to improve their performance against energy shielding.

History
Coilguns and railguns are a concept that dates back to before humanity's first solar colonies were established, although until the 24th century, they were never fully adopted outside of test models. Early coilguns and railguns tended to be too bulky, too technologically and too power-hungry to be viable as weapons, and the lack of opponents with any appreciable armor meant that neither the UNSC nor their CMA counterparts bothered pursuing the concepts. Instead, innovations were tested and funded in the private sector, where surface-to-orbit mass drivers were incrementally improved over the centuries. It was not until the Inner Colony Wars that they fully replaced electrothermal naval guns, though they still remained a rare sight on warships.

The onset of the UNSC-CMA Cold War of the late-2400s saw the technology being matured further.