Dr Gerald Bull, a Canadian, had been working on long range artillery shells and a gun the GC 45. In 1977 he came into contact with a South African Arms manufacturer who produced improvements to the design of the gun.

Bull was arrested by the US in 1980 and sentenced to 12 months of which he served 6. Upon release he set up operations in Brussels. Meanwhile the South Africans continued their work on developing the gun and in 1982 they put it into service as the GC 5. Its range was far superior to any other weapon of its type. They saw service in the Angolan war and soon dominated.
Noricum, the arms division of Voest-Alpine purchased the design rights to the GC-45. They made a number of detail changes to improve mass production, resulting in the GHN-45 (gun, howitzer, Noricum). Bull was soon contacted by Iraq, who placed a $300 million contract for 110 guns from Noricum in Austria. Deliveries were made in 1984 and 1985, eventually raising the number to 200 guns.
In Iraq the guns had a similar effect on the ongoing Iran–Iraq War as the G5 had in Angola, stopping any push by the Iranians deeper into Iraq. Bull was requested to improve deliveries any way he could. Bull then arranged a deal to deliver G5's from South Africa. By the time of the Gulf War, about 124 of these weapons had been delivered. Bull and Saddam Hussein became partners in a number of future ventures. These ventures are generally believed to be the cause of Bull's assassination.