From DownSights: “The new Cold War Zombies’ map Firebase Z is here, and of course, with it comes a brand new wonder weapon called The RAI K-84. This is a play on words with the Ray Gun and a Rifle being combined to form an assault rifle prototype of the Ray Gun pistol.
This guide shows you exactly how you can get this wonder weapon for free via a side-easter egg. Other methods include doing trials and spinning the mystery box. But, this method guarantees acquiring the rare legendary weapon as you will build it yourself.
Acquiring the RAI K-84 won’t be as easy as the D.I.E. Shockwave from Die Maschine. A bit of work will be required to get the RAI K-84. The guide continues assuming you’ve already turned on the power and built the Pack-A-Punch machine. If you haven’t, then it is recommended that you first check out our guide on doing that.”