20×138mmB
The 20×138mmB or Long Solothurn cartridge is a type of ammunition used mainly for anti-aircraft and anti-tank weapons during World War II. The designation means the caliber is 20 mm, the length of the cartridge case is 138 mm and B indicates it is a belted case. The loaded cartridge weighs 10.7 oz.
Also recorded as 20 x 138 mm Belted · Long Solothurn · 20x138mmB · 20 mm L/138
20×138mmB
Esquilo · Johan Fredriksson · CC BY-SA 3.0
- Name
- 20×138mmB
- Field
- cannon cartridge
- Period
- 1930
- Region
- Switzerland
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Documentary summary
The 20×138mmB or Long Solothurn cartridge is a type of ammunition used mainly for anti-aircraft and anti-tank weapons during World War II. The designation means the caliber is 20 mm, the length of the cartridge case is 138 mm and B indicates it is a belted case. The loaded cartridge weighs 10.7 oz.
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Authority files
wikidata · Q4630843 · wikipedia · 20×138mmB
In this article
Key facts
Key facts
• Name — 20×138mmB • Origin — Switzerland • Type — Anti-armor/anti-air • Used By — Switzerland, Germany, Italy, Finland, Poland • Wars — World War II • Design Date — 1930 • Manufacturer — Swiss Solothurn • Variants — Long Solothurn • Is Si Specs — yes • Case Type — Bottleneck, belted • Bullet — 20 mm • Neck — 20.9 • Shoulder — 25.5 • Base — 26.86 • Rim Dia — 28.48 • Rim Thick — 26.86 • Case Length — 138 • Length — 202.7 • Bw1 — 4.1 oz • Vel1 — 2950 ft/s • En1 — 34655 ftlb-f • Balsrc — Rifles and Machine Guns
History
History
• Illustration — Three Finnish and Italian 20×138B cartridges next to a 37mm anti-tank shell The 20×138mmB cartridge was developed by the Waffenfabrik Solothurn, a Swiss front company of Rheinmetall in the early 1930s from a less powerful cartridge 20×105mmB cartridge.
Weapon platforms
Weapon platforms
The 20×138mmB cartridge is used in the following weapons:
Switzerland
Switzerland
• Solothurn anti-tank rifles: S-18/1000 and S-18/1100 • Solothurn ST-5 20mm AA Gun
Germany
Germany
• FlaK 30 and FlaK 38 single-barrel, and Flakvierling quadruple-barrel anti-aircraft guns • KwK 30 and KwK 38 vehicle-mounted weapons • MG C/30L aircraft gun
Italy
Italy
• Cannone-Mitragliera da 20/65 modello 35 (Breda) • Cannone-Mitragliera da 20/70 (Scotti)
Finland
Finland
• Lahti L-39 anti-tank rifle • Lahti L-40 anti-aircraft gun
Poland
Poland
• Nkm wz.38 FK anti-tank vehicle-mounted gun
Chronology
Dated record
Chronology
The full dated record · 2 entries
1930
20×138mmB first recorded.
1930
20×138mmB is recorded from 1930.
Places
Named by the record
Places
Only places the record itself states, plotted where the house gazetteer settles their coordinates. Nothing is inferred from a name or a nationality.
- Switzerland
Primary material
Documents and archives
authority record
- Wikidata, structured authority record Q4630843: 20×138mmB
Unverified · Wikidata
reference work
- “20×138mmB”, English Wikipedia, consulted as further reading
Reputable secondary · Wikipedia
Citations
References
Each reference names the institution holding it, so a reader may go to the document itself.
authority record
Partially resolvedreference work
Partially resolved
The Encyclopedia exists whether or not anything is for sale. Corrections are recorded rather than overwritten, and every version of this record is kept. Published 14 August 2026.
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