Rapid Additively Manufactured Ballistics Ordnance: RAMBO
The US Army has developed a grenade launcher. And a grenade. Both made by 3D printers:
Researchers at the U.S. Army Armament Research, Development and Engineering Center (ARDEC) successfully fired the first grenade created with a 3-D printer from a grenade launcher that was produced the same way. This demonstration shows that additive manufacturing (commonly known as 3-D printing) has a potential future in weapon prototype development, which could allow engineers to provide munitions to Soldiers more quickly.
And they get points for the name.