The aviation technology that appeared at the end of the Second World War left no doubt about one simple fact: the existing anti-aircraft weapons were already outdated. In the very near future, all available anti-aircraft guns will not only lose their effectiveness, but also become practically useless. Something completely new was required. However, a lot of time remained before the creation of full-fledged anti-aircraft missiles, and it was necessary to protect the airspace now. The increase in aircraft flight altitudes led the military of several countries to a kind of "enthusiasm" for anti-aircraft guns of especially large caliber. For example, in the late forties and early fifties in the USSR, designers worked on a project for a 152 mm KM-52 gun.
At the same time, in the UK, the development of anti-aircraft systems also went in the direction of increasing the caliber. Until 1950, two development projects were carried out under the names Longhand and Ratefixer. The goal of both programs was to increase the caliber of the anti-aircraft guns and at the same time increase the rate of fire. Ideally, the guns of these projects were supposed to be some kind of hybrids of large-caliber anti-aircraft guns and small-caliber rapid-fire assault rifles. The task was not easy, but the British engineers coped with it. As a result of the Longhand program, the 94mm Mk6 gun, also known as the Gun X4, was created. The Ratefire program led to the creation of four 94-mm cannons at once, designated by the letters C, K, CK and CN. Until 1949, when Ratefire was closed, the rate of fire of the guns was brought to 75 rounds per minute. The Gun X4 entered service and was used until the late 50s. Products of the Ratefire program, in turn, did not go to the troops. The result of the project was only a large amount of materials related to the research side of the design of such artillery systems.
All these developments were planned to be used in a new, more monstrous project. In 1950, RARDE (Royal Armament Research & Development Establishment) chose the famous Vickers company as the developer of the new system. The original terms of reference spoke about the creation of a rapid-fire anti-aircraft gun of 127 mm (5 inches) caliber with a water-cooled barrel when firing and with two drum magazines for 14 rounds each. The automatics of the gun was supposed to work at the expense of an external source of electricity, and an arrow-shaped feathered ammunition was offered as a projectile. The fire control of the new weapon, according to the assignment, was to be carried out by one person. Information about the location of the target and the necessary lead was given to him by a separate radar and a computer. To facilitate development, Vickers received all the necessary documentation for the Ratefire project. The project was named QF 127/58 SBT X1 Green Mace.
The task given to Vickers was very difficult, so RARDE was allowed to first make a smaller caliber gun and work out all the nuances of a full-fledged gun on it. The smaller caliber of the test gun was actually larger than that of the Longhand and Ratefire programs - 4.2 inches (102 millimeters). The construction of an experimental "small-bore" gun under the designation 102mm QF 127/58 SBT X1 ended in the 54th year. The eight-meter barrel of this gun, together with recoil devices, two barrel-shaped magazines, guidance systems, an operator's cab and other systems, eventually pulled almost 25 tons. Of course, such a monster required some kind of special chassis. As this, they chose a special six-wheeled towed trailer. All the units of the experimental gun were installed on it. It should be noted that the trailer was able to fit only a tool with a fastening system, magazines and an operator's cab. The latter was a booth similar to the cabin of modern truck cranes. Since the aiming of the gun, the reloading and pumping of water to cool the barrel were carried out with the help of electric motors, the complex had to include separate machines with an electric generator and a stock of shells. And that's not counting the radar station needed to detect targets and aim a gun at them.
The 102-mm anti-aircraft miracle went to the training ground in the same 1954 year. After a short test firing to test the recoil devices and the cooling system, full-fledged checks of the automation began. Using the capabilities of the electric drive of the loading system, the testers gradually increased the rate of fire. By the end of the year, he managed to bring it to a record value of 96 rounds per minute. It should be noted that this is a "pure" rate of fire, not a practical one. The fact is that the reloading mechanics could issue these same 96 shots, but two "barrels" with 14 shells in each, by definition, could not provide a salvo of at least half a minute with the maximum rate of fire. As for the replacement of stores, on an experienced 102-mm cannon of the Green Mace project, this was done using a crane and took about 10-15 minutes. It was planned that after working out the systems of the gun itself, means of quick reloading would be developed. In addition to the record rate of fire, the gun had the following characteristics: a 10, 43-kilogram sub-caliber feathered projectile left the barrel at a speed of more than 1200 m / s and flew to an altitude of 7620 meters. Rather, at this height, acceptable accuracy and reliability of destruction were ensured. At high altitudes, due to the aerodynamic stabilization of the projectile, the effectiveness of the destruction dropped significantly.
By the spring of the 55th tests of the experimental 102-mm cannon were over and the Vickers company began to create a full-fledged 127-mm gun. And this is where the fun begins. The Green Mace project is already not particularly well-known, and as for its later stages, there are more rumors and assumptions than concrete facts. It is only known that the designers' plans included two versions of the "Green Mace" - smooth-bore and rifled. According to some sources, the QF 127/58 SBT X1 gun was built and even managed to start testing. Other sources, in turn, claim some problems during development, due to which the prototype of the 127-mm cannon could not be built. The approximate characteristics of the "full-size" weapon are given, but there is still no exact data. One way or another, all sources agree on one thing. In 1957, taking into account the unsatisfactory characteristics of the Green Mace project in terms of reach and accuracy, the British War Department ceased work on rapid-fire large-caliber anti-aircraft artillery. At that time, the global trend in the development of air defense was the transition to anti-aircraft missiles and the "Green Mace", even without completing the tests, risked becoming a complete anachronism.
As if trying to save an interesting project from such "shame", RARDE closed it in 1957. Before the adoption of the first version of the Bloodhound anti-aircraft missile system, there was less than a year left.
