Chain gun

[1][2] In 1972, Hughes Helicopters began a company-funded research effort to design a single machine gun to fire the U.S. Army's M50 20 mm round.

[1][2] In April 1973, the program fired test rounds in more powerful 30 mm WECOM linked ammunition, from a prototype A model.

One link of the chain is connected to the bolt assembly, moving it back and forth to load, fire, extract, and eject cartridges.

The other two periods, when the chain moves across the "short" sides of the rectangle, sideways relative to the axis of the barrel, determine how long the breech remains locked while firing, and open to allow cartridge extraction and ventilation of fumes.

An unclassified report on the EX-34 prepared by the Naval Surface Weapons Center in Dahlgren, Virginia, dated September 23, 1983, said that:29,721 rounds of endurance tests were fired with no parts breakage and without any gun stoppages ...