Solothurn-Arsenal

The gun used 20×105mm belted-case ammunition which it shared with the S 18-350 aircraft cannon that was developed from the rifle. A Finnish source gives armour penetration of the gun (probably achieved with the Hungarian APHE-T round, since it was the only type used in Finland) as 20mm at a 60-degree angle at 100-metre distance, decreasing to 16mm at 500 metres. A variant of this design, the Solothurn-Arsenal, was manufactured without license in Estonia before WW2; however only 20 were produced prior to Soviet occupation. In March 1940, with funds collected in Switzerland to help the Finnish war effort in the Winter War, Finland bought twelve S 18-154 anti-tank rifles from Solothurn, though the purchaser was nominally the Swiss army. The weapons arrived in Finland during the spring after the war had ended, but they were later used in the Continuation War. However, the guns were soon found to be obsolete in their intended role. Various models of the S-18 series, including the Solothurn S-18/1000 and the Solothurn S-18/1100 were also used by Switzerland, the Kingdom of Hungary, Nazi Germany, the Kingdom of Italy, and the Netherlands. The Waffenfabrik Solothurn firearms company was owned by the German firm Rheinmetall, and used the Swiss company to manufacture arms which were prohibited for manufacture by any German firm to get around arms limitations imposed upon them at the end of the First World War.

• Name — Solothurn S-18/100 20 mm anti-tank cannon • Origin — Nazi Germany Switzerland • Type — Large caliber rifle, anti-materiel rifle • Is Ranged — Yes • Used By — See Users • Wars — Slovak-Hungarian War World War II • Production Date — 1934–1943 • Variants — Solothurn S-18/1000, Solothurn S-18/1100, Solothurn-Arsenal • Weight — 45 kg without magazine • Length — 1760 mm • Part Length — 925 mm • Cartridge — 20×105mmB • Caliber — 20 mm • Action — API blowback • Rate — Semi-automatic • Velocity — 735 m/s with a Hungarian APHE-T Armour-piercing high explosive tracer round • Range — 400 m (for penetration of 50mm armor) • Feed — 10-round detachable box magazine • Sights — A dedicated scope

The Solothurn-Arsenal was a reverse-engineered copy of the S-18/100, manufactured without license in Estonia between 1938 and 1940. Apart from the prototypes, only 20 were produced and deployed with the 1st and 7th Infantry Regiment by the time of the Soviet invasion in 1940.

• Illustration — 20 mm Tankbüchse Solothurn S-18/100 • Illustration — Soldier in Russia, S-18/100

• Kingdom of Bulgaria - 308 ordered in 1936 • Estonia: 4 bought in 1936 for testing, reverse-engineered as Solothurn-Arsenal • Finland: 12 S-18/154 • Nazi Germany: some for trials • Japan: 1 S-18/100 bought in 1936 for comparison with type 97 automatic cannon • Kingdom of Hungary (1920–46): Produced under license as 36M 20mm Nehézpuska and used extensively throughout WW2. Used on 38M Toldi light tank and 39M Csaba armored car. • Kingdom of Italy: some for trials in 1934 • Netherlands: 6 for trials in 1937 • Switzerland: some for trials • United States: 2 S-18/100 purchased in 1939 for trials at Aberdeen Proving Ground • Kingdom of Yugoslavia