This Machine

 is a weapon in Fallout: New Vegas.

Characteristics
 appears to be a pre-war M1 Garand, in excellent condition when first acquired. It is chambered in .308 and holds eight rounds at a time, and is essentially a unique Hunting Rifle of sorts.

Locations
is given to you by Contreras for not turning him in at the end of Free Quest: Dealing with Contreras, Camp McCarran. However, It seems it can also be gotten by hacking his computer and turning him in as well, as they "confiscate" it off him.

Appearances
appears in Fallout: New Vegas.