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 .
History
The 20×138mmB cartridge was developed by the , a Swiss front company of Rheinmetall in the early 1930s from a less powerful cartridge 20×105mmB cartridge.
Weapon platforms
The 20×138mmB cartridge is used in the following weapons:
Switzerland
Solothurn anti-tank rifles: S-18/1000 and S-18/1100
Solothurn ST-5 20mm AA Gun
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
Cannone-Mitragliera da 20/65 modello 35 (Breda) Cannone-Mitragliera da 20/77 (Scotti)