The highly successful 2cm FlaK 30 series of guns used by Germany in World War II was developed from the Solothurn ST-5, a 20mm anti-aircraft gun designed by Solothurn in Switzerland, itself an enlarged Solothurn MG30. Solothurn was owned by the German firm Rheinmetall, which along with all other German manufacturers was prohibited from developing certain weapons under the terms of the Versailles Treaty. The partnership with Solothurn was a common way to circumvent restrictions. The ST-5 fired the “Long Solothurn” ammunition – the most powerful 20 mm round available.Heavily illustrated, this title discusses the development of the famous 2cm FlaK 38 together with its predecessor, the 2cm FlaK 30, and also the lightweight 2cm Gebergs FlaK 38 and the 2cm Flak vierling. It discusses the uses of the gun in World War II, and its various mounts on both trucks and tank chassis. By the end of the war over 17,500 of these guns were in service.