12.8 cm FlaK 40
The 12.8 cm FlaK 40 was a German World War II anti-aircraft gun. Although it was not produced in great numbers, it was reportedly one of the most effective heavy AA guns of its era. History. Development of the 12.8 cm FlaK 40 began in 1936, with the contract being awarded to Rheinmetall Borsig. The first prototype gun was delivered for testing in late 1937 and completed testing successfully. The gun weighed nearly 12 tonnes in its firing position, with the result that its barrel had to be removed for transport. Limited service testing showed  this was impractical, so in 1938 other solutions were considered. Ultimately the firing platform was simplified, based on the assumption it would always be securely bolted into concrete. Approximately 200 guns were also mounted on railcars, providing limited mobility. The total weight of the "Flakzwilling" twin-gun mount system reached 26.5 tonnes, making it practically impossible to tow cross-country. In the end, this mattered little since by the time the gun entered production in 1942, it was used in primarily static, defensive applications. There were four twin mounts on the fortified anti-aircraft Zoo Tower, and they were also  on other flak towers protecting Berlin, Hamburg, and Vienna. It is claimed that during the Battle of Berlin the guns on the Zoo Tower were used successfully to support ground forces. The rush to capture the Reichstag led to dozens of tanks being destroyed. The gun fired a 27.9 kg (61.5-pound) shell at 880 m/s (2,890 ft/s) to a maximum ceiling of 14,800 m (48,556 ft). Compared with the 88 mm FlaK 18 & 36, the FlaK 40 used a powder charge four times as great. In December 1943, Hitler decided not to introduce the FlaK 40 "During  this war".