20×138mmB
| 20×138mmB | ||||||||
|---|---|---|---|---|---|---|---|---|
| 20×138B cartridge and a tape measure in centimeters | ||||||||
| Type | Anti-armor/anti-air | |||||||
| Place of origin | Switzerland | |||||||
| Service history | ||||||||
| Used by | Switzerland, Germany, Italy, Finland, Poland | |||||||
| Wars | World War II | |||||||
| Production history | ||||||||
| Designed | 1930 | |||||||
| Manufacturer | Swiss Solothurn | |||||||
| Variants | Long Solothurn | |||||||
| Specifications | ||||||||
| Case type | Bottleneck, belted | |||||||
| Bullet diameter | 20 mm | |||||||
| Neck diameter | 20.9 mm (0.82 in) | |||||||
| Shoulder diameter | 25.5 mm (1.00 in) | |||||||
| Base diameter | 26.86 mm (1.057 in) | |||||||
| Rim diameter | 28.48 mm (1.121 in) | |||||||
| Rim thickness | 26.86 mm (1.057 in) | |||||||
| Case length | 138 mm (5.4 in) | |||||||
| Overall length | 202.7 mm (7.98 in) | |||||||
| Ballistic performance | ||||||||
| 
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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 300 grams (10.7 oz).