The M12 Servant is by far the oldest deep-space weapon to date. Despite its age it still sees use across all civilized systems and is mounted on pretty much every militarized vessel.
Though initially meant to destroy debris and small spacefaring projectiles,
it became clear that it was more than a tool for defense.
In the early years, during the long peace this was the weapon that threatened
traders and civillian vessels. And most historians think its one of the numerous reasons for Earths total militarization.
It is fairly accurate and its high-explosive projectiles can melt armor and ripp fighters apart.
Its small size and universal mount allows it to be mounted on pretty much every ship.
The M12 Servant uses 14mm high-explosive depleted uranium shells.
Because there is no air-resistance in space a bullet that is fired is only affected by the gravitational pull of celestial objects or G-Drives. Because of that the perfomance of conventional weapons is boosted, most ships that mount M12 Servants use an R-AI to use them effectively.
In the early 21st century most people believed that a conventional firearm cannot be fired in space. That believe was based on the assumption that oxygen was needed in order for the bullet to ignite. However even the most primitive firearms of Earths past used their own oxidiser and the M12 Servant is no exception.
It is fired via an electircal impulse given by the fire-control-center on board a ship.