Gerald Bull, a Canadian-American weapons engineer, invested much time and effort into developing artillery shells of longer range than what was being had previously in the Cold War period (1947-1991). During the 1970s, through his Space Research Corporation (SRC) in Canada, he designed the "GC-45", a towed 155mm field howitzer system which was eventually adopted by many national powers while going on to see local production by some. The GC-45 became Bull's major claim to fame and his expertise in the field, coupled to his relationship with the Iraqi government at the time, ultimately led to his assassination by an unknown party.
The original, base GC-45 weighed 18,120lb and sat on a four-wheeled split-trail carriage assembly. The mounting hardware allowed for elevation and traversal of the gun tube in the usual way. Rate-of-fire could reach up to five rounds-per-minute sustained and maximum firing range was 40 kilometers. The breech was of a conventional interrupted thread screw. A gun shield was optional, the recoil system integrated to the mounting hardware and the barrel was capped by a large slotted muzzle brake.
Three shells were eventually devised by Bull: ERFB-BB (Base Bleed), ERFB (Full Bore) and HE M107. The ERFB-BB weighed 48 kilograms and had a muzzle velocity of nearly 3,000 feet-per-second with a range out to 39.6 kilometers. The ERFB weighed 45.5 kilograms and was rated at 2,940 feet-per-second with a range out to 29.9 kilometers. The HE M107 weighed 43 kilograms, was rated at 2,210 feet-per-second and ranged out to 17.8 kilometers. The shells were specifically designed with a focus on range and not so much accuracy (dispersion).
In 1977, Bull teamed with South Africa's Denel which resulted in a new mounting system being developed that incorporated a small powerplant for relocating the artillery piece under its own power over short distances (the weapon could still be towed as normal). Further development by Denel ultimately produced the local "G5" gun system detailed elsewhere on this site.
Bull then relocated to Europe and continued his own development work under the brand name of Noricum. This period produced its own product, the "GHN-45", which incorporated newer features and refinements that caught the attention of China, Israel, Singapore and Thailand (local production of this weapon took place in China, Israel and Singapore). From there, Bull became involved with Saddam Hussein's Iraq which sought a long range weapon to keep the Iranians at bay. Arms embargoes limited much of the importation possibilities of the GHN-45 so the South African G5 was substituted for in some cases. Some GHN-45 guns were used by Iraq during the 1991 Gulf War though many were destroyed where they sat in the subsequent coalition offensive.
The FGH-155 became a further development of the GC-45 which revised the rifling work and the FGH-203 was a 203mm caliber form with exceptional range (up to 50 kilometers). The latter was fitted to a 6x6 wheeled chassis by the Iraqi Army to produce the "Al-Fao" Self-Propelled Howitzer (SPH) vehicle at one point - another joint venture with the Iraqi government which put Bull in the crosshairs of both Israel and Iran.
In all, Bull's guns were taken on by the forces of China, Iran, Iraq, Israel, Kuwait, Saudi Arabia, Singapore, South Africa, Thailand and Turkey. Bull himself was assassinated in 1990. Production of his systems, which began in 1980s, continues in one form or another today (2017) while many have seen combat actions in the various wars of the 20th and 21st centuries.