Gauss weapons as a category can be used to describe two styles of weapons: railguns, and coilguns.
Railguns require contact between the projectile and two rails, and a current is passed through them, accelerating the projectile to absurd velocities.
Coilguns, however, fire a depleted uranium projectile jacketed in steel. When triggered, a small “kicker” charge is activated to begin the launch, and then the round is electromagnetically accelerated to full speed in the barrel of the firearm. Stabilized in flight with fins integrated into the core of the projectile, these are exceptionally accurate even over long distances.