It is obtainable only via console command on PC. This weapon can not be found anywhere in the game. A side-by-side comparison of both Gauss rifles, the beta and the 'official', tested on multiple targets from multiple angles seems to confirm this. For some reason this off-center trajectory remained unchanged in the 'official' version, leading many players to confusing missed shots, because visually the round appears to be dead-center despite the fact that the actual coded path for the round remains up and to the right. When one fires the beta version, the round clearly fires quite a ways up and to the right of the center of the scope.
The beta version is especially interesting because, when fired, it shows the true trajectory of the Gauss rifle's shots, where as the 'official' version of the weapon shows a misleading visual representation of the bullet trajectory. It is only obtainable through console commands. When used in V.A.T.S., any hit will do exactly 95.244 of the maximum damage, regardless of enemy damage threshold. It only does about 25% of the damage of the final version, but has a 100% knock-down chance. PC Playstation 3 Xbox 360 The Gauss rifle in Fallout: New Vegas is almost identical to the one found in Fallout 3, and thus suffers from similar bugs, including the one that affects its damage output when fired via V.A.T.S.
The beta Gauss rifle is a beta version of the scoped Gauss rifle that uses the model of a laser rifle and features a five round magazine.
The Beta Gauss rifle is a cut weapon in Fallout 3. The following is based on Fallout 3 cut content and has not been confirmed by canon sources.