Gauss rifles shoot bullets, not plasma. They operate by accelerating a ferrous projectile to high speed using an electromagnetic coil. Which is also ridiculously energy-inneficient, Railguns perform the same task using far less energy because of they way they accelerate the projectile, and it doesn't even need to be ferrous, just any conductor of electricity.
I have an incredible idea that would make this mod better. What if you added reflectors to send some lasers right back at the enemy? That would be a tool in PvP, or to reflect Ghast Fireballs. The device, when reflecting, would create a hexagon, emitting from the character, to protect and reflect from projectiles. Reflectors will dominate the world. Also, make a unique reflector for the aliens that doubles the projectiles speeds. To make to make to balanced, your movement will be slowed, so cowering in that hexagon won't protect you from the slap of a hand (or sword, whichever you prefer). Also, if you activate it while someone is near, they will be knocked back a far distance. When falling, you can spam this in mid-air to stop all vertical acceleration. The mod is looking great.
Crafting Recipe (Coal = Ender Pearls)
I will update it when 1.3 comes out and it will be made in custom stuff because i think it is hard and tough to code and takes more time to update mod, i got lots homework and learning but with custom stuff is easier.