The US Army RDECOM published a YouTube video on the Picatinny Arsenal YouTube Page about Additive Manufacturing, which includes 3D printing, and the Rapid Additively Manufactured Ballistics Ordnance or RAMBO Launcher. RAMBO, in this case, is fundamentally a 3D printed version of the M203A1 40mm grenade launcher as well as 3D printed M781 training ammunition.

All the components found in the M203A1 grenade launcher, except springs and fasteners, was produced using AM techniques and processes, including selective laser sintering, wax printing, fused deposition modeling, urethane molding and lost wax casting.

The Rambo project was basically a proof of concept demonstration of the Additive Manufacturing, or AM process for the production of military arms and armament. The speed at which using Additive Manufacturing allows something as complex as the M203A1 to be prototyped and manufactured far surpasses traditional, subtractive manufacturing and skips right past any expensive, time-consuming tooling. This in turn allows research and development to make changes in programs and manufacturing far quicker than traditionally.

The .38-caliber cartridge needed for the propulsion of the M781 was the only component of the training round that was not printed.

The 3D printed grenade launcher and 3D printed training rounds were live-fire tested back in October 2016, at Picatinny Arsenal. The testing included firing 15 AM-manufactured rounds with no issues and best of all, no barrel wear. The AM-made system reportedly passed with flying colors.

Selective Laser Sintering Parts

The printed RAMBO along side its more plebeian issued M203A1

AM Manufactured 40mm Projectiles and Windscreens