The Faderator is a unique variant of the Gauss rifle, which in appearance is identical to the standard weapon. Its actual properties are considerably different, with the following distinctions: a lower ammunition usage per shot, larger ammunition capacity, automatic operation, very high hit chance in V.A.T.S., tons of knockback, and a dramatically increased rate of fire, bringing the weapon's calculated damage-per-second to 20,160.
It shoots a spread of 3 shots with one trigger pull, similar to a shotgun. In V.A.T.S. it fires 12 shots, with 3 rounds per shot, bringing the total number of rounds fired to 36.
Based on these factors, as well as the weapon only appearing in one normally inaccessible test cell, it can be assumed that The Faderator was never meant for legitimate inclusion in the add-ons. Like the Debug 9mm and The Disintegrator laser rifle, it's likely that The Faderator was a weapon designed to help developers and playtesters get through combat as quickly as possible, which is further backed up by the low skill and Strength requirement for effective use.
The Faderator cannot be found anywhere in the game, and can only be obtained through the use of console commands or use of game save modding tools. Also, it can be found in a room where the player can be transported to with console command coc testmentats.
Every major add-on (Dead Money, Honest Hearts, Old World Blues, Lonesome Road, and Gun Runners' Arsenal) has its own version of The Faderator. All versions are exactly the same (in stats, name, ID, etc.) but different version Faderators will not group up when they are in the same condition percentage since the game considers them different weapons.
The Faderator has unlimited ammunition. It will use your ammunition if you have some (max charge, bulk, etc.), however your ammunition will not go down. (You only need one cell of the ammunition you want to use because of its breeder effect.)
Due to the massive rate of ammunition regeneration from the microfusion breeder effect, the gun can be fired continuously without its ammunition reaching 0.
If you have the Fast Shot trait, firing this weapon fully automatic may cause your game to run slowly until you stop firing it.
When fired, there is a chance of obtaining Drained microfusion cells. When combined with the Vigilant Recycler perk, firing the weapon excessively, then recycling the drained microfusion cells gained can supply the Courier with unlimited ammunition of this type for use with other weapons.