Solothurn S-18/100
A semi-automatic bullpup anti-tank rifle firing 20 mm ammunition.
The Solothurn S-18/100 was a 20 mm anti-tank cannon used during World War II, designed by both German and Swiss engineers. Its semi-automatic action was housed in a bullpup layout. The weapon fired powerful 20×105mm belted-case rounds, the same ammunition used in the S 18-350 aircraft cannon developed from the rifle. Recoil was severe due to the large cartridge, and the gun’s size made it difficult to carry. It fed from a five- or ten-round magazine attached horizontally on the left side. According to a Finnish source, armor penetration—likely with the Hungarian APHE-T round, the only type used in Finland—was 20 mm at a 60-degree angle at 100 meters, dropping to 16 mm at 500 meters.
An unlicensed copy, the Solothurn-Arsenal, was reverse-engineered in Estonia before World War II, but only 20 were completed before the Soviet occupation. In March 1940, Finland bought twelve S 18-154 anti-tank rifles from Solothurn using Swiss funds collected for the Winter War, though the Swiss army was listed as the buyer. These arrived after the war ended but saw use in the Continuation War, where they quickly became obsolete. Other models in the S-18 series—including the S-18/1000 and S-18/1100—were used by Switzerland, Hungary, Nazi Germany, Italy, and the Netherlands. The manufacturer, Waffenfabrik Solothurn, was owned by the German firm Rheinmetall, which used the Swiss company to produce arms forbidden to German firms under post-World War I restrictions.
Quick Facts
- Origin
- Nazi Germany / Switzerland
- Is Ranged
- Yes
- 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
Facts from the source article.
Lore & Background
The Solothurn S-18/100 was developed by Waffenfabrik Solothurn, a Swiss company owned by the German firm Rheinmetall. This arrangement allowed the manufacture of arms prohibited for German firms under post-World War I restrictions. The weapon's large, powerful ammunition produced tremendous recoil, and its size made portability difficult.
A variant, the Solothurn-Arsenal, was reverse-engineered and manufactured without license in Estonia between 1938 and 1940, with only 20 produced before Soviet occupation. Finland purchased twelve S-18/154 rifles in March 1940 using Swiss funds, arriving after the Winter War but later used in the Continuation War, though they were soon found obsolete in their intended anti-tank role.
The S-18/100 and its variants (including the S-18/1000 and S-18/1100) were used by Switzerland, Hungary, Nazi Germany, Italy, the Netherlands, and other nations. Hungary produced it under license as the 36M 20mm Nehézpuska and used it on the 38M Toldi light tank and 39M Csaba armored car.
Reader's Guide
The Solothurn S-18/100 represents an early attempt to field a semi-automatic anti-tank rifle with substantial firepower, though its practical limitations were significant. The weapon's bullpup configuration was unusual for its time, and its use of 20 mm ammunition gave it considerable armor penetration at short ranges—20 mm at 100 meters against a 60-degree angle—but the recoil and bulk hindered portability. Its development was shaped by the interwar arms restrictions that forced German firms like Rheinmetall to operate through Swiss subsidiaries. The S-18/100 saw service in multiple European armies, including those of Switzerland, Hungary, Italy, and the Netherlands, and was produced under license in Hungary. However, by the time of the Continuation War, it was already considered obsolete for its primary anti-tank role. The Estonian Solothurn-Arsenal copy, of which only 20 were made, highlights the weapon's limited but notable spread. The S-18/100's legacy is as a transitional design between World War I anti-tank rifles and later, more effective anti-tank weapons, and it remains a distinctive example of a bullpup firearm in a heavy-caliber role.
Did You Know?
- The Solothurn S-18/100 used a 20×105mm belted-case cartridge shared with the S 18-350 aircraft cannon.
- A Finnish source gives armor penetration as 20 mm at a 60-degree angle at 100 metres, decreasing to 16 mm at 500 metres.
- The Solothurn-Arsenal was an unlicensed Estonian copy of the S-18/100, with only 20 produced before Soviet occupation.
- The Waffenfabrik Solothurn was owned by the German firm Rheinmetall to circumvent post-WWI arms restrictions.
More in Sniper Rifles 1-22
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced