ARDEC cobalt alloys show promise for sustained firepower

PICATINNY ARSENAL, N.J. — During a firefight, the last thing a machine gunner wants to do is stop fighting to change barrels, but that’s how it has always been done with standard, single steel-barrel machine guns.

The reason for the barrel change is that at high temperatures barrels lose “strength properties,” according to engineers working on a promising alternative.

One of the engineers is Vinny Leto, Systems Project Engineer, of the ARDEC Weapons System Technology Directorate. During a test firing of a proof-of-concept barrel in December, Leto witnessed a measure of success with the High Performance Alloys for Weapons Applications Project.

During testing, the first rifled, cobalt-alloy machine gun barrel ever produced using the “flow forming” process consistently reached high temperatures without degraded performance.

The proof-of-concept barrel was made of an alloy that contains more than 50 percent of the metal cobalt. Cobalt alloys are erosion- and corrosion-resistant metals that are designed to retain high strength during long-term exposure to high temperatures.

Cobalt alloys are frequently used in the aerospace industry, such as the hot-gas section of turbine engines, explained Leto. Cobalt alloys are also used as short liners for machine gun barrels.