What could be the most powerful machine gun in human history is being developed by Chinese scientists and engineers.
This weapon consists of five or more barrels, with each barrel capable of firing bullets at a rate of 450,000 rounds per minute. The resulting barrage has an unprecedented density, capable of intercepting hypersonic missiles travelling at speeds exceeding Mach 7.
In comparison, the maximum firing rate of the US military's most powerful Phalanx system is only 4,500 rounds per minute.
Refilling ammunition for a weapon that consumes millions of bullets per minute has been considered an insurmountable challenge. But Chinese researchers in Taiyuan, an industrial hub in central China, have come up with an ingenious solution: a container-like, replaceable magazine filled with barrels, each packed with bullets. Once the bullets are fired, the disposable barrels are simply discarded along with the whole container.
This box-type rotary firing technology can "improve loading speed, reduce the decrease in barrel strength and accuracy due to repeated loading, and achieve the combat objectives of multiple strikes, continuous operations and rapid counter-attacks", the project team led by Lu Xutao, an associate professor of mechanical and electrical engineering with the North University of China, wrote in a peer-reviewed paper published in the Chinese Journal of Detection & Control in December.
Traditional machine guns use mechanical triggers, but they cannot keep up with the demand by the People's Liberation Army (PLA) for 7,500 shots per second. To solve this problem, Lu and his colleagues developed an electronic trigger consisting of coils.
The contactless trigger can instantly melt the alloy wire embedded in the bullet, forming a high-energy metal jet that ignites the explosive. With unprecedented efficiency, this electronic trigger has a firing time of only 17.5 microseconds. Test data confirms that it "is sufficient to achieve the target performance of 450,000 rounds per minute per barrel", Lu's team wrote.
This weapon, also known as the Metal Storm, was first proposed by Australian inventor Mike O'Dwyer in the 1990s. Metal Storm Inc, founded by O'Dwyer, produced a 36-barrel test system that reached a firing rate of 1 million rounds per minute.
In 2006, O'Dwyer told the media that the PLA had approached him and offered US$100 million for the technology. The US Department of Defence took notice and collaborated with O'Dwyer to develop new weapon systems for the battlefield. However, due to technical and other challenges, the project was ultimately abandoned, and Metal Storm Inc declared bankruptcy in 2012.
China has continued to invest in this technology, mobilising national scientific and technological resources for systematic research and development. According to publicly available information, some teams are focusing on the extremely complex basic physical problems involved in sequentially firing bullets loaded tightly in the barrel. Some teams have developed test bullets with sensors and chips, while others are focusing on reducing the cost and improving the reliability of disposable barrels.
These efforts have made significant progress in recent years. Many scientists, including Lu, now believe that China's own version of the Metal Storm weapon could surpass the Western prototype from a decade ago by at least 10 times in firing rate and find its place in many military applications.
In future wars, "the speeds of weapons such as missiles and aircraft will continue to increase", Lu said.
"Metal Storm weapons have already become essential equipment for defending territorial waters and airspace."