It only differs from the regular Gauss rifle in damage, which scales to the Courier's level.

Elijah wields a non-playable version of the Gauss rifle.

It can only be obtained without the Wild Wasteland trait, otherwise it will be replaced by the alien blaster.

YCS/186 - A unique variant that does over 16% more damage and uses four microfusion cells per shot instead of five.

The Gauss rifle can fire a total of about 395 times using standard cells, the equivalent of 395 reloads, from full condition before breaking. With the Heavyweight perk, it comes down to 60 cells, equivalent to 12 shots. In Hardcore mode, if more than 260 microfusion cells, or 52 shots, are carried, the Gauss rifle becomes heavier than the anti-materiel rifle. It does still apply force to nearby enemies on projectile impact, though that force is largely negated unless the target is dead, in which case it will typically send the target's corpse flying. The Mojave Wasteland version of the Gauss rifle also lacks the knock-down effect that the Fallout 3 version had. Ammunition is also harder to come by than other weapons this is coupled with its requirements of five microfusion cells per shot, as opposed to its Fallout 3 counterpart, which required only one.

Like most other energy weapons in Fallout: New Vegas, this weapon is hard to maintain Gauss rifles are rare in the Mojave, therefore making it more difficult to repair. In appearance, it is almost identical to the Gauss rifle acquired after finishing the Fallout 3 add-on Operation: Anchorage, apart from the addition of an extra pad on the buttstock. The scoped Gauss rifle is an advanced sniper rifle that uses a series of eleven electromagnetic coils to energize and magnetize a preloaded standard projectile round to a tremendous speed.

Fallout 4 new vegas weapons