A high-tech railgun at this point would make more sense than a conventional cannon and is the likely answer.
Satellite imagery has revealed two unusually large artillery pieces, measuring about 80 ft and 110 ft respectively, at a test centre for armour and artillery northwest of Baotou in China.
The two pieces, which are horizontally mounted, are mounted on a concrete pad that appeared between September 2010 and December 2011, when the two pieces were first captured by satellite imagery. Images provided by Astrium confirmed that the objects were still in place in July 2013.
The 2011 imagery clearly depicts a series of what appear to be targets in front of the 110 ft piece, suggesting some kind of penetration testing for high-velocity projectiles.
China has historically shown interest in large calibre, long-range artillery. It experimented with the Xianfeng ‘supergun’ in the 1970s as part of Project 640 anti-ballistic missile programme. Approximately 85 ft long, Xianfeng may be the smaller of the two objects retained for experimental use after its cancellation in 1980.
In the 1990s it was revealed that China had built a long-range ‘supergun’ technology testbed similar to the Iraqi Project Babylon supergun designed by Gerald Bull. IHS Jane’s Land Warfare Platforms: Artillery & Air Defence notes that Bull was heavily involved in designing long-range Chinese artillery systems for Norinco in the 1980s.
Although the Baotou pieces appear similar in design to the Bull ‘supergun’ concept, it seems unlikely that they are intended for long-range artillery barrages or anti-satellite operations given China’s extensive long-term development of ballistic missiles for both of these missions.
Alternatively, the devices could also be railgun prototypes, although this appears unlikely as there is no significant external power routed to the test pad and a lack of environmental protection. The other possibility is that China is simply reusing the legacy systems from its long-range artillery programmes from the 1970s and 1990s as part of a projectile test range – a view that is supported by the presence of what appears to be ‘used’ targets on the northwest side of the pad.
Full article: Satellite imagery reveals mystery ‘supergun’ in Chinese desert (IHS Janes 360)