The primary amrament of the Ancient warfleet and the main defensive weapon utilized to protect their outposts from hostiles.
The Drone as we know it today was perfected roughly 10 million Earth years B.C. Although adjustments and changes may have been made over the millenia they stayed pretty much the same. The Drone was one of the pinnacles of Ancient weapons technology. A perfect weapon for destroying both fighters and capitol ships.
The Ancients put defensive outposts on most of their worlds. These outposts can/do store many thousands of Drones. Drones work best when powered by zero point energy.
Drones are powerful pin point accuracy weapons. They can be deployed to destroy fighters and incomming missiles or to target the vital systems of a capitol vessel. Drones are surrounded by a powerful E.M/Kironic field which allows them to pass through virtually any type of force shield. Only Ancient/Asuran and higher tiers of Asgard shields have been observed blocking them. It is said that the shields of an Ori warship also withstood a Drone barrage, but it seemed as though the Ori warship took damage. Even the most advanced Goa'uld shields do not slow down a Drone. It is unlikely that the shields of any milky way power besides the Tau'ri could stop a Drone weapon.
Drones can also generate a energy field that allows them to burrow through certain forms of matter, such as ice. They can sustain hard impacts without detonating as they are not usually set to impact detonation but are controlled by a combination of the Drones A.I system and the firing persons mind.
A anti infantry weapon perfected in the Pegasis galaxy.