Green Mace was probably the ultimate medium / heavy anti-aircraft gun. It was developed by RARDE (Royal Armament Research and Development Establishment) to fill a requirement for a rapid firing heavy anti-aircraft gun. Various studies had been carried out, such as "Ratefixer" to establish the maximum firing rate for AA guns.
Green Mace was designed as a solution to the rate of fire question in that it carried a pair of fourteen round magazines on the gun itself. Green Mace was capable of being fired by a single NCO and all its functions were electrically powered. With an intended calibre of 5" (12.7cm) Green Mace was also capable of firing high velocity discarding sabot darts (similar in concept to anti-tank rounds).
A 4" (10.2cm) calibre version was built and tested, with a rate of fire in the region of 96 rounds per minute. A new predictor, Red Sea, was developed for use with these new guns, but like the guns themselves, were cancelled in favour of guided weapons.
A related medium anti-aircraft gun wasRed Queen.
Photo courtesy of "Firepower - The Museum of Royal Artillery"
Anti-Aircraft Guns or Colour Codes