Railguns are high-velocity projectile weapons, developed by the Tau'ri in 2005, which use electromagnetic fields to propel a solid metal slug at a high velocity. The close in defensive railguns of the Tau'ri fire a slug at a velocity of mach 5 over a distance of 250 miles. A standard magazine carries ten thousand rounds, with the gun itself firing at a rate of 500 rounds per minute. One standard magazine should therefore, allow for twenty minutes of sustained fire. (SGU: "Air, Part 1", SGA: "The Siege, Part 2")
They have become standard on F-302 fighter-interceptors, the BC-303 Prometheus, and all Daedalus-class vessels for ship-to-ship combat. They are also used to defend ground bases, such as Icarus Base. As of 2007, when Asgard plasma beam weapons were retrofitted on all BC-304s, railguns are mainly used as a secondary, point defense weapons (or CIWS) due to the fact that larger capital ships, particularly shielded ones, are much more resistant to railgun fire than are smaller fighter craft. (SGU: "Air, Part 1", SGA: "Be All My Sins Remember'd")
Just a few shots from a railgun are able to take out a Wraith Dart or Goa'uld Death Glider relatively quickly. (SG1: "Prometheus Unbound", SGA: "The Siege, Part 3") However, against capital ships, their effectiveness varies. An untested Earth Ship, Odyssey fired its railguns which did "minimal damage" against three Goa'uld Ha'tak Motherships belonging to the Lucian Alliance. Railguns have proven to be less effective against Hive ships due in part to the sheer size of such vessels and the density of their organic hulls. (SG1: "Off the Grid", SGA: "No Man's Land") Furthermore, (like all weapons with the exception of Asgard plasma beam weapons, and potentially also Ancient Drone weapons) they have proven ineffective against Ori shields. (SG1: "Camelot", "Unending", "The Road Not Taken")
However, against vessels that posses shields but have them deactivated, railguns have proven quite effective at quickly penetrating such vessels' hulls and causing serious damage. During the Battle of Asuras, an opening salvo from a 304's railguns proved powerful enough to cause severe damage to an unshielded Asuran-built Aurora-class battleship, possibly leading to its destruction. (SGA: "Be All My Sins Remember'd")
Railguns saw their first use in 2005 during the Battle of Atlantis. Several RG/BBT SG military mounted guns originally slated to be fitted to the Prometheus were positioned around Atlantis and used as stationary turrets to defend the city against waves of incoming Wraith Darts. While these guns were successful in defending the city, the sheer number of darts and eccentricity of their movement limited these weapons' effectiveness to an extent. (SGA: "The Siege, Part 3")
Following the Daedalus' arrival in the Pegasus galaxy, its railgun turrets have been used in battle against Wraith ships in numerous occasions. In 2005, the Daedalus' railguns were used against the Wraith fleet attacking Atlantis. On the Daedalus' subsequent mission to destroy 12 Wraith Hive ships during the Battle of Atlantis, railguns were used to provide defensive fire. (SGA: "The Siege, Part 3") Shortly after this event, railguns on an F-302 piloted by John Sheppard were used to destroy a sensor array on the Daedalus after it began broadcasting the ship's location. (SGA: "The Intruder") Later, during the Battle of Edowin, railguns were used against two Wraith Hive ships. In this engagement, the Daedalus' railguns were fired at both ships simultaneously, drastically reducing their effectiveness as the ships were ultimately destroyed by other means. (SGA: "The Hive")
Railguns saw extensive usage during the Battle of the Void in 2006. During the various skirmishes of that engagement, the Daedalus railguns were used against the two Hive ships heading for Earth. Near the conclusion of the battle, the Daedalus brought all main railguns to bear on one of the Hive's main dart bays. In the ensuring barrage of railgun fire, the projectiles from these weapons impacted the Hive's Dart bays at incredible speeds, completely destroying the incoming darts moments after they launched. The concentrated fire on the bays also created a number of secondary explosions inside the ship which stopped the Hive from firing and left the entrance to the bay in a fiery cloud. (SGA: "No Man's Land") Towards the end of 2006, the Daedalus utilized limited railgun fire to simulate on an attack on M4D-058. (SGA: "The Game")
In the Milky Way galaxy, railguns saw use on the Odyssey's first mission in a battle against three Lucian Alliance-controlled ha'taks. Later in 2006, the Korolev and Odyssey utilized railguns during the Battle of P3Y-229. However, they ultimately proved ineffective against the shield of the four Ori warships they faced. (SG1: "Camelot")
In 2008, railguns were utilized during the Battle of Asuras. In the Apollo's opening salvo, railguns were fired at an unshielded Aurora-class battleship, ultimately leading to its destruction. The F-302s that participated in the battle also used railguns and missiles to target the Asuran's ships' hyperdrive engines. (SGA: "Be All My Sins Remember'd") Railguns were later used by F-302s during an attack on Michael's cruiser and its complement of darts over M2S-445. (SGA: "Search and Rescue") F-302s later saw further engagement against a force of Wraith Darts over Area 51. (SGA: "Enemy at the Gate")
In 2009, railguns were utilized extensively during the Battle of Icarus Base. During an attack by the Lucian Alliance, Icarus Base utilized its network of RG/BBT SG military mounted guns for defense. Furthermore, the base's complement of F-302s utilized railguns and missiles to destroy incoming fighter-craft. While these guns were initially successful in fending off the attacking Death Gliders, the base quickly became overrun, necessitating its evacuation. Meanwhile, in orbit of the planet, the George Hammond utilized railguns in fending off the three attacking Ha'tak as well as their numerous support ships. (SGU: "Air, Part 1")
Behind the scenesEdit
In reality, the technology exists to build Railguns. The Railguns in development and testing by the U.S. military are able to catapult a football size projectile to mach 7. Real-life Railguns also sound very different from those portrayed in Stargate (not to mention that there is no sound in space) - while the Stargate Railguns make a high-pitched firing sound, a real railgun produces a deafening, low-pitched boom when firing (a result of superheated gases expanding violently as the projectile leaves the turret).
Railguns currently in development and limited deployment generally face 4 main problems, all of which seemingly have solutions through the introduction and acquisition of materials and technology through the Stargate program.
- Power: Currently the biggest obstacle to practical railgun deployment is the amount of power needed to generate the high electric current and magnetic fields for effective target penetration. A small naquadah generator connected to the weapon is more the capable of supplying the necessary power requirements. Close up shots of railguns deployed on Atlantis during the Battle of Atlantis shows a miniature naquadah generator mounted on top of the railguns.
- Heating: The rails on a railgun are subjected to extreme heat due to the high currents running through it and the frictional heat generated from the high velocity of the projectile fired. The temperature can even rise to the melting point of the rails. Theoretically, rails made from naquadah alloys similar to the ones use on the hull of F-303 and F-304 battlecruiser, will be able to withstand the heat generated on top of being a highly conductive metal able to channel the electric current.
- Repulsion: When electricity runs through each armature of the railgun, it produces a proportional repulsive force on each other. Adding the wear and tear from rapid firing of high velocity rounds, they threaten to bend the rails out of shape, making it ineffective. The properties of trinium could significantly reduce this effect as it is 100 times stronger and lighter than steel.
- Portability: Because of its massive power requirements, all currently developed railguns have to be mounted on capital ships large enough to house a generator capable of supplying its power demands. Obviously, these generators are very large and aren't easy to move around, making the weapon system impractical for deployment in most scenarios and locations. On the other hand, a soccer ball sized naquadah generator, coupled with a design that incorporates Naquadah and Trinium alloys, allows one to create a railgun that is small enough to be sent through a stargate intact and deploy it almost anywhere you want. Truly remarkable.