Plutonium

what mod do I need?

Ive been dabbling in the commands recently and I came across the give command. People have said that you can give yourself any gun in the game in zombies with it but Ive looked around and I cant figure out what I need to type to actually spawn the weapon in.

I figured it would just be "give HAMR" but I guess its not that simple?

any help would be greatly appreciated.