Stargate Railguns
| Name | Type | Scale | Caliber | Space Range | Atmosphere Range | Damage |
| Type I | Railgun | Walker | 12.7mm | 1-5/13/25 | 1-500/1,300/2,500m | 3D+2 |
| Type II | Railgun | Starfighter | 20mm | 1-5/13/25 | 1-500/1,300/2,500m | 3D |
| Type III | Railgun | Starfighter | 30mm | 1-5/13/25 | 1-500/1,300/2,500m | 3D+1 |
| Type IV | Railgun | Starfighter | 40mm | 1-5/13/25 | 1-500/1,300/2,500m | 3D+2 |
| Type V | Railgun | Starfighter | 75mm | 1-5/13/25 | 1-500/1,300/2,500m | 4D+2 |
| Type VI | Railgun | Starfighter | 85mm | 1-5/13/25 | 1-500/1,300/2,500m | 5D |
| Type VII | Railgun | Starfighter | 105mm | 1-10/25/50 | 10-1,000/2,500/5,000m | 5D+1 |
| Type VIII | Railgun | Starfighter | 120mm | 1-10/25/50 | 10-1,000/2,500/5,000m | 5D+1 |
| Type IX | Railgun | Starfighter | 155mm | 1-10/25/50 | 10-1,000/2,500/5,000m | 5D+2 |
| Type X | Railgun | Starfighter | 210mm | 1-10/25/50 | 10-1,000/2,500/5,000m | 6D |
| Type XI | Railgun | Starfighter | 300mm | 1-10/25/50 | 10-1,000/2,500/5,000m | 6D+1 |
| Type XII | Railgun | Starfighter | 420mm | 1-10/25/50 | 10-1,000/2,500/5,000m | 7D+1 |
| Type XII | Railgun | Starfighter | 500mm | 1-10/25/50 | 10-1,000/2,500/5,000m | 7D+2 |
| Type XIV | Railgun | Capital | 1,000mm | 1-10/25/50 | 2-20/50/100km | 4D+1 |
| Type XV | Railgun | Capital | 2,000mm | 1-10/25/50 | 2-20/50/100km | 5D+1 |

"That is a big gun." ―Eli Wallace
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.
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.
Source:
- Stargate Wiki: Railgun
- Stargate SG-1 First Steps: The Stargate Unexplored Words Roleplaying Sourcebook (page 166)
- thedemonapostle