Oh boy even more science from Wriggle!

Types of Astra:
Astra: The most basic of all magic bullets that travels at 200 mph. Astra bullets are fired from Cygnus' two pistols, Altair and Vega (named after two stars with a tragic story behind.) They do not damage physically, but instead eats away at the target's magic source. It takes 30 or so Astra to deplete the mana source from ordinary students, 50 for regular RP characters, 80 to 200 for characters with originally high mana pool, like Lynne, Trista, or graduate students, and 300+ for teachers.
Astra - Helios: Fire elemental.
Astra - Selena: Ice elemental.
Astra - Jupiter: Lightning elemental.
Astra - Oort: Non-elemental bullets, similat to regular Astra, that travels slower than regular Astra but takes away mana twice as much.
Astra - Comet: Non-elemental Astra bullets that move twice as fast but deals half of the mana damage.
Astra - Supernova: Highly explosive Astra that, when striking a surface, works as a flash bang. Is entirely non-destructive.
Astra - Black Hole: Entirely black Astra bullets that slow the targets in addition to the mana damage.
Astra - Quasar: Entirely white Astra bullets that does the opposite: makes the targets faster for a short time.
These are just a few of many.
So they do not deal physical damage, but takes away mana or the magic energy. This makes Cygnus' guns non-lethal, but still damaging.