It is uncannily similar to Starsiege Tribes' disc launcher, both in looks, design, and execution. Originally, the design for the disc launcher in Starsiege Tribes was that discs would be fired at about one every 1-2 seconds, but later mods were introduced (and became the accepted primary design) that increased the discs' firing speed (and travelling speed) to rapid-fire, long-distance shots, similar to that of the plasma gun.
Let me see if I can dredge up a picture...
*edit*
Here's an in-game picture about what I'm talking about.
And
PlanetTribes' description of the original disc launcher.